Question about 1999 Toyota Corolla

2 Answers

Toyota 1999 Corolla LE major hesitation issues! I had a crack exhaust manifold and had it replaced and while I was at it, I had the o2 sensor replaced since it was right there. then after repair, I started to notice hesitation now and then when I went from stop light to going. it started to get worse and worse over the month and was hit and miss when it would happen. Mechanic said it was a faulty new o2 sensor, so I had it swapped with another one. Same issue remained. I changed out whole exhaust line minus second post-cat o2 sensor thinking might be a clogged cat, but same issue, so I changed it back and was able to return the whole system (got lucky!). Then I replaced MAP sensor per another suggestion, and didn't help (then was able to return with more luck!). Then I replaced IAC (Idle Air Control valve) and throttle sensor and intake throttle body gaskets, and still same issue but left them for less repair issues down the road and harder to swap out. I then replaced camshaft sensor and still same issue. I then cleaned up injectors and replaced all the o-rings and injector cushions (noticed old where cracking) and replaced spark plugs with some really good ones and still same issue. I then thought most likely a fuel filter if not at engine, which is in tank on 99 corolla, so I replaced it and the pump and strainer all in one shot so it wouldn't have to be opened again, and STILL same issue. I pulled speed sensor and cleaned and put back in thinking that might not do much more than tell dash speed, etc. We know this: When car is in open loop (just started and under 2 minutes of running) it runs great and picks up great when you put on the gas and runs as it should. Then when it goes to close loop, it will totally lose power if you accelerate on the gas and have to REALLY work it up slowly to get going any speed. If you hold your foot on the gas then the RPMs will jump up and down by 1000rpm every couple seconds as it doesn't seem to know what to do or something, but speed will stay the same or slow down a little. SO we know it isn't all the other options the parts store suggested and leaves me with only two items left to replace? the Crankshaft Sensor and the ECM module/computer. The problem has been the symptoms seem possible with several of the parts I have replaced but hasn't been doing it every time OR sending an error light so mechanics don't get right solutions either as they can't replicate it all the time. This is REALLY costing me time and parts to get fixed. PLEASE HELP! I think I might as well put a crankshaft sensor on it so I know all sensors are in good order for the future, but don't know if that will fix it or not and it is another $90 on top of the $350 I have spent already on this issue. I don't want to pay to have someone tell me it is something I can replace as they can't seem to tell me what it is exactly either.

Posted by Anonymous on

  • 3 more comments 
  • Anonymous Apr 27, 2011

    I will be sure to try this out tonight. I have never heard of doing this, but will try anything! :) so as it is reving, spray a little water into the intake and it will help to clean the system? cool.

  • Anonymous Apr 27, 2011

    in the 99 corolla they put the filter WITH the pump in the tank...oh the fun of that year. It is a half black circle that the gas regulator and the pump hook into and only could be bought through the dealership and local parts placed don't even show as existing but said it was built into the pump. I replaced it all wanting to know that it wasn't fuel deliver to the engine in any way, thinking it for sure had to be one of the two after all the other stuff I had done (thinking filter or pump or both) and not wanting to have to open it all back up again.

  • Anonymous Apr 27, 2011

    I am confused on that one on how to do it. the gas pressure regulator is in the tank attached to the filter. small part but like $80 to replace and the one thing I didn't replace. Either way, how would I test it from under the hood? I see the line coming from the tank, past the fire wall, and I think then going to injector bar? Can a mechanic test it easily enough without having to pull from tank? maybe I should have replaced it when it was all opened up. Could it be that if the car runs great for the first couple minuted then struggles for gas/fuel/(even air?) despite a new filter and pump and stainer? The charcoal canister is back under by the tank - could that be acting up? I know nothing of what it does or what issue are when it goes bad.

  • Anonymous Apr 27, 2011

    Would the Knock sensor play a factor in any of the symptoms I am having? the fuel filter in the 99 corolla is by pump in the tank, and gas pressure regulator and pump both hook into it. I replaced everything but the gas pressure regulator.

  • Anonymous May 02, 2011

    ISSUE FOUND (or so it seems!) - thanks everyone for your help. I talked with my cousin who is a mechanic in colorado and he told me the oxygen sensors made by bosch lately have really gone down in quality and seem to work on european cars ok but on asian cars they have been bad. I had put a new bosch on, then replaced it a couple weeks later as local mechanic said it seemed faulty, then ruled out the second one being an issue. I replaced it again with a DENSO one that was made for the car per my cousins brainstorm, and it WORKED. I have one nice running car now with a good o2 sensor, new fuel pump and filter, new injectors rings and cushions, iridium spark plugs, throttle body intake gasket, and much more etc. I do have to say this experience did show other issues that might pop up that I now don't have to worry about. THANKS AGAIN!

×

Ad

2 Answers

Randy Ohler

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Toyota Master
  • 14,585 Answers

I seen that you replace the throttle gasket, was the throttle body cleaned when this was done. I have found that when cars start to hesitate there are three main reasons( in my experience).
the air filter, The mass air flow sensor,(if you have one), And a dirty throttle body. I take a can of brake clean and clean the throttle body as far as I can into it with a brush, cleaning the back of the plates also. Spray the mass air flow sensor clean and replace the air filter. This almost always gets rid of the hesitation. One some cars it's like putting a new engine in, it can be so dramatic. Every tune up I do starts here. Once I done cleaning the parts I use part of the cleaner and spray into the throttle as the car is running. Just a note , when you clean the throttle, it will take a second or two to stat the car.

Posted on Apr 27, 2011

  • 11 more comments 
  • Anonymous Apr 27, 2011

    thanks for input. I took the whole throttle body intake off and cleaned all areas and checked everything really well when I did the other sensors in that area. 2000 and above have a MAF, but 99 has a MAP (Manifold Absolute Pressure sensor) and an AIT sensor (Intake Air Temp sensor) that work together to accomplish the same as the MAF from my understanding. Both seem to test ok. Will an ECM computer act up like that or will it usually be a sensor or filter still? air filter seems ok as well, but maybe I will change it to totally rule it out.

  • Randy Ohler Apr 27, 2011

    Just remove the filter to see if thats the problem. If it helps replace it, if not save your money.
    Ecm's don't make the car hesitate. they usually make them run really bad or not at all. Don't replace the crank sensor it's not bad. what you might check is the timing belt. you can remove the top cover to inspect it. Toyota's are very particular about thier timing. These belts have to be tight, I mean really tight. the first one I did to the book and would not start, checked and rechecked and had the boss check, no start. Finally I called a dealer and the tech told me to put a pry bar against the tensioner and lay on it as I tighten the bolt. Did this and it purred like a kitten. So if you get any slack,even a little in the belt. this is where your problem lies. Heck you already replaced everything else. Randy

  • Randy Ohler Apr 27, 2011

    The belt is about a $700.00 job at a shop.These jobs are not that difficult to do. Takes me about 4 hours. If you do it replace everything in there. Timing belt kit and water pump. You only want to do this one time.

  • Anonymous Apr 27, 2011

    Also good feedback. I replaced the timing belt, tensioner, gears, front and back guides and water pump exactly a year ago as a the tensioner was going bad and you could hear the chain vibrating when it ran, and once replaced it was much quieter. it was done by a shop and was the $700 amount or so. Even when chain wasn't tight, it still ran ok. I called parts store and they also don't recommend the crankshaft sensor, so that is one less thing I can change on my own but the issue still remains. Maybe I need to still check the chain again then?

  • Randy Ohler Apr 27, 2011

    Ok. I have another try and see. This wont cost . Remove the air plenum and get a spray bottle with water in it. start the engine , let it warm up. Rev the engne and spray the water into the throttle body. What this does is cleans all the carbon build up off everything in the cylinder And the valves. Do this 2 or 3 times as you want to make sure you get all the cylinders.

  • Anonymous Apr 27, 2011

    I also noted today that when it was acting up at the stop light after it was warmed up and not wanting to excel when gas was applied, if I put into neutral and pushed on gas, then the RPMs and engine sounds fine, but when it was in gear again, it acted up again and would have total power hesitation. After some coughing and sputtering, it would pick up real quick, then hesitate, then maybe pick up a little more, or hesitate as it saw fit depending if I was going light on the gas, pumping it, or trying to floor it, etc. The speed sensor (VSS?) that is in the trans case wouldn't play a part in that would it? Thought that only told speed to dashboard? I also took the crankshaft sensor off and cleaned it and make sure it at least wasn't sludged up, etc. last night and still acting up today the same. So it seems to be something that isn't acting up in open loop, but when it goes to close loop, it is having issues with gas/air/flow. THANKS for any help!!!

  • Randy Ohler Apr 27, 2011

    In your first note you had said that you replaced the pump and strainer. Did you actually replace the fuel filter. I believe they are up by the engine drivers side mounted on the fender well. The strainer and filter are different. They only vehicle that I know of or have changed a filter that was in the tank was my truck. What a rip. Never seen one before or since.

  • Randy Ohler Apr 27, 2011

    Yeah. If you have ever done a head gasket job and noticed that one of the cylinders really clean. that was from the coolant/water going threw that cylinder.
    Also you might want to check the fuel pressure regulator. Pull the vacuum lines if gas comes out it is bad. If your not sure crimp the return line thus not letting any pressure escape.

  • Anonymous Apr 27, 2011

    In the 99 corolla they put the filter WITH the pump in the tank...oh the fun of that year. It is a half black circle that the gas regulator and the pump hook into and only could be bought through the dealership and local parts placed don't even show as existing but said it was built into the pump. I replaced it all wanting to know that it wasn't fuel deliver to the engine in any way, thinking it for sure had to be one of the two after all the other stuff I had done (thinking filter or pump or both) and not wanting to have to open it all back up again.

    gas pressure regulator is in the tank attached to the filter. small part but like $80 to replace and the one thing I didn't replace. Either way, how would I test it from under the hood? I see the line coming from the tank, past the fire wall, and I think then going to injector bar? Can a mechanic test it easily enough without having to pull from tank? maybe I should have replaced it when it was all opened up. Could it be that if the car runs great for the first couple minuted then struggles for gas/fuel/(even air?) despite a new filter and pump and stainer? The charcoal canister is back under by the tank - could that be acting up? I know nothing of what it does or what issue are when it goes bad.

    Would the Knock sensor play a factor in any of the symptoms I am having? the fuel filter in the 99 corolla is by pump in the tank, and gas pressure regulator and pump both hook into it. I replaced everything but the gas pressure regulator.

  • Randy Ohler Apr 27, 2011

    The knock sensor feels for pings, main spark knock, and adjust the timing accordingly. If the lifters are tapping it would also feel that, but it would advance the timing abit. this would give you a little better accelleration . The charcoal canister rarely goes bad, usually when some one breaks it like me. As far as the regulator goes it can be tested with a fuel pressure guage. Hook it up when the car is acting up. it will have to have enough hose to be on the outside of the hood and in the cabin of the car, not many people/mechanics have that much extension. Then the car has to be driven , under a load, And the pressure read, if it drops below specs then the regulator is bad. Pumps will put out more than what is required to run the engine. ie... regulate the pressure. One sign the the regulator is bad is to much fuel consumption. A good mechanic will use the hand held computer to his advantage, he must remember numbers for most every sensor. This is how I can tell customers what is wrong with there vehicles, instead of "I think this is bad, NO then it is this,NO", Every car I do goes on the computer because tune ups don't always make it run better. Reading the numbers is what makes it run better. Question? when you had the manifold replaced, was it new or from a junk yard? Reason I ask I had a leak at the manifold flange before an 02 sensor. Made the light come on and had lower than normal gas mileage, I don't remember if I had hesitation, But it ran kind of sluggish.
    If they used a junk yard manifold and didn't have it surfaced flat this could possible be a problem. Not for sure through. Randy

  • Randy Ohler Apr 27, 2011

    Hey fixya is a pain to go threw so here's my email if you [email protected]

  • crushbox May 24, 2011

    Hi!!!! my car have has the same problem as yours and its drives me crazy. Please let me know if you solve the problem

  • Randy Ohler May 24, 2011

    ISSUE FOUND (or so it seems!) - thanks everyone for your help. I talked with my cousin who is a mechanic in colorado and he told me the oxygen sensors made by bosch lately have really gone down in quality and seem to work on european cars ok but on asian cars they have been bad. I had put a new bosch on, then replaced it a couple weeks later as local mechanic said it seemed faulty, then ruled out the second one being an issue. I replaced it again with a DENSO one that was made for the car per my cousins brainstorm, and it WORKED. I have one nice running car now with a good o2 sensor, new fuel pump and filter, new injectors rings and cushions, iridium spark plugs, throttle body intake gasket, and much more etc. I do have to say this experience did show other issues that might pop up that I now don't have to worry about. THANKS AGAIN

×

Ad

cobrajocky

  • Level 1:

    An expert who has achieved level 1.

    New Friend:

    An expert that has 1 follower.

  • Contributor
  • 1 Answer
Ad

Add Your Answer

×

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Show me location of oxygen sensor, bank 1 on Toyota Corolla, C E, 2000


oxygen sensors(O2S) are located after the cat converters
heated oxygen sensors (HO2S) are located in the exhaust manifold/ exhaust pipe before the cat converters
they are different sensors performing different jobs so rich or lean problems will be the HO2S in the manifold

May 07, 2018 | Toyota Cars & Trucks

1 Answer

How do I locate the oxygen sensor of Toyota corolla 1994 1.8i


O2 sensor is normally sticking out of the exhaust manifold

Oct 06, 2016 | 1994 Toyota Corolla

1 Answer

Where is the oxygen sensor located in the 2000 Toyota Corolla?


Depending which O2 sensor it is, it will be located after the exhaust manifold before or after the Catalytic Converter.

Jun 24, 2010 | 2000 Toyota Corolla

3 Answers

Where is the rear O2 sensor in a 1995 corolla


It will be just after the catalytic converter in your exhaust.

Nov 09, 2009 | 1995 Toyota Corolla

1 Answer

I need to replace the O2 sensor, where is it located and how many? Also are they all the same size?


There are 2 O2 sensors on your vehicle.
Bank 1 sensor 1 is located in the back of the motor bolted to the exhaust manifold at the frontpipe to manifold union.
Bank 1 sensor 2 is located underneath the vehicle right after the convereter.
The first one is held on by 2 12 mm nuts the second one is a screw in type that requires a 22mm or 7/8" wrench to remove

Sep 19, 2009 | 1998 Toyota Corolla

1 Answer

Why i cant find any o2 sensor in my 1992 toyota corolla AE101, 4A-FE engine?


check it if you have near the exhaust manifold. its like a sparkplug connected to thin wire.

Jul 04, 2009 | 1992 Toyota Corolla

1 Answer

96' toyota corolla Exhaust Manifold Keeps Cracking


Sounds weird that this problem keep occurring over and over. Does it crack in the same spot every time?

Only two things I can think of that would cause this problem.
1. Extensive over heating, I've seen a exhaust manifold get glowing red hot because of a bad oxygen sensor.

2. Excessive Vibration. The whole exhaust line to the back of the car is moving around too much or too stiff. The exhaust line needs to move around enough to take the movement/vibration of the engine. I would check out for bad motor mounts and worn out exhaust pipe mounts.

May 17, 2009 | 1996 Toyota Corolla

2 Answers

O2 sensor on a 1994 toyota tercel


Usually the O2 sensor will be on the exhaust manifold close to the engine, I'm going to assume you have a pretty good idea of what you are doing so if you need more details don't hesitate to ask.

Oct 30, 2008 | 1994 Toyota Tercel

Not finding what you are looking for?
1999 Toyota Corolla Logo

3,057 people viewed this question

Ask a Question

Usually answered in minutes!

Top Toyota Experts

Marvin
Marvin

Level 3 Expert

85239 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22485 Answers

Jeffrey Turcotte
Jeffrey Turcotte

Level 3 Expert

8984 Answers

Are you a Toyota Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...