Question about 1993 Subaru Impreza

4 Answers

Misfire/Backfire and not accelerating properly wondering whats the problem?

I was driving on a broken exaust right where my rear cat was and the fixed it (weld) then it start to not accelerate properly and then I found out that my air filter was kind of open it wasn't sealed properly so I sealed it meanwhile I have never changed my filter so maybe that's a problem? I also was revving the engine and I keep hearing this popping noise as soon as I press the pedal not all the time but occasionally. I went under the hood and found out that the popping noise sounds like its coming from air filter cabin anyone have any ideas on whats goin wrong with the car?

Posted by on

Ad

4 Answers

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    MVP:

    An expert that got 5 achievements.

    Sergeant:

    An expert that has over 500 points.

    Governor:

    An expert whose answer got voted for 20 times.

  • Subaru Expert
  • 180 Answers

1st get a new air filter I recommend a quality brand like the oem one or purolator.
2nd remove and clean the maf sensor. Start with the screw clamp on the intake hose. Then unplug the sensor just squeeze the tab and wiggle it off. Now remove the 4 - 10mm boltsthat hold the maf sensor on the air box. Use caution as some models have a housing with brackets that are loose when the above 4 bolts are removed.
Next clean the air flow sensor using crc maf cleaner or other maf sensor safe cleaner. This is necessary as the sensor gets dirty as the miles accumulate. Make sure the sensor wires are very clean and let it fry for 30 mins before re-installing the sensor.

I would inspect the blower motor for debris as a 93 impreza doesn't have a cabin filter.
You can access the hvac fan from under the glove box see the attached video for how to. I know its not the correct subaru but the procedure is the same. Misfire/Backfire and not accelerating properly won - misfire-backfire-not-accelerating-tq5sh21jzhkdedjt044n20r3-4-0.jpg

Posted on Dec 15, 2014

Testimonial: "i did tjis problem still occurring when im on the highway trying to quickly make it to work on time the rpm needle has problem getting me to the destination quick enough. what I mean is the rpm needle jumps up and down even tho my foot is holding steady pressure on the accelerator if I decide to give it a little more pressure it starts to make a popping noise sounds like its coming from cabin very confusing could it be from my throttle body?? throttle positioning sensor ?maybe"

Ad
  • Level 1:

    An expert who has achieved level 1.

    MVP:

    An expert that got 5 achievements.

    Hot-Shot:

    An expert who has answered 20 questions.

    Corporal:

    An expert that has over 10 points.

  • Contributor
  • 46 Answers

Check cam shaft timing, park plugs, HT leads. If all okay, backfiring is a sign of a lean mixture, can be the MAF sensor or low fuel pressure, fuel pump problems are very common, but also a MAF sensor broken contact.

Posted on Dec 15, 2014

Ad
  • Level 1:

    An expert who has achieved level 1.

    Corporal:

    An expert that has over 10 points.

    Mayor:

    An expert whose answer got voted for 2 times.

    Problem Solver:

    An expert who has answered 5 questions.

  • Contributor
  • 6 Answers

Air filter not sealed and never replaced, you should clean the MAF sensor since the dirt passes through the air filter.

Posted on Dec 15, 2014

Testimonial: "i did tjis problem still occurring when im on the highway trying to quickly make it to work on time the rpm needle has problem getting me to the destination quick enough. what I mean is the rpm needle jumps up and down even tho my foot is holding steady pressure on the accelerator if I decide to give it a little more pressure it starts to make a popping noise sounds like its coming from cabin very confusing could it be from my throttle body?? throttle positioning sensor ?maybe"

  • Level 1:

    An expert who has achieved level 1.

    MVP:

    An expert that got 5 achievements.

    Hot-Shot:

    An expert who has answered 20 questions.

    Corporal:

    An expert that has over 10 points.

  • Contributor
  • 44 Answers

You should spray with MAF/TB cleaner to clean throttle body(TB) too. While you're there, spray the IACV Intake Assist Control Valve. If your RPM fluctuates, most likely the carbon build up block the air to assist idling when engine is COLD. IACV is located at front/top of throttle body. If you found carbon dust build up in IACV, you solve your issue.

Posted on Jan 30, 2015

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of.(from cars to computers, handyman, and even drones)
click here to download the app (for users in the US for now) and get all the help you need.
Goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

1 Answer

Poor acceleration


Check your spark plugs.

Oct 02, 2013 | Nissan Cars & Trucks

1 Answer

Flashing service engine light 2000 oldsmobile silhouette


flashing lites means dont drive .bad things will happen in motor. something emission related messing with exaust ' dont drive!!!! take to smog tech'

Nov 21, 2012 | 2000 Oldsmobile Silhouette

1 Answer

Well i did not pass emissions a code 0420 came up when i go to push on the gas i takes a while to go so there is loss of power in my car


The PCM copares switch rates between the front O2 sensors and the downstream catalyst moniters. The catylist moniters are often mistaken as O2 sensors, and they are, but that is not their job, or what they are called. By comparing the switch rates between the front (before cat) and rear (downstream of cat) the PCM knows if the cat is affecting the exaust, and how much it is affecting the exaust. If it sees little or no effect o the exaust gases that have passed through the cat, then it decides that the cat is not working anymore, ad sets a P0420, or a P0430, depending on which bank it is. To check this yourself, you will need to bring up data stream on your scanner, watch the upstream and downstream O2 parameters and see if they are following each other closely. If the cat is working right, you should see a fairly rapid switch rate, probably 5 or 6 times a minute on the front O2, but almost a flat line just above .5 volts on the rear. If the rear is switching often you proabably need a catalytic converter.

Hope this helps, James Booth!! PLEASE RATE THIS!!!:)

May 18, 2011 | Toyota Celica Cars & Trucks

1 Answer

NEED DRIVE CYCLE FOR 2004 CRV TO RESET CAT AND O2 MONOTOR


Here is the info

NOTE: The ignition key must not be on prior to the cold start otherwise the heated oxygen sensor diagnostic may not run.

1. As soon as the engine starts, idle the engine in drive for two and a half minutes with the A/C and rear defrost on. OBDII checks oxygen sensor heater circuits, air pump and EVAP purge.

2. Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle. OBDII checks for ignition misfire, fuel trim and canister purge.

3. Hold at a steady state speed of 55 mph for three minutes.

OBDII monitors EGR, air pump, O2 sensors and canister purge.

4. Decelerate (coast down) to 20 mph without braking or depressing the clutch. OBDII checks EGR and purge functions.

5. Accelerate back to 55 to 60 mph at half throttle. OBDII checks misfire, fuel trim and purge again.

6. Hold at a steady speed of 55 to 60 mph for five minutes.

OBDII monitors catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors and purge functions.

7. Decelerate (coast down) to a stop without braking. OBDII makes a final check of EGR and canister purge.

Oct 02, 2010 | 2004 Honda CR-V

1 Answer

PO420 CATALYS INEFFICIENCY BELOW THRESEHOLD BANK 1.REPLACED CAT, 02,?


The PCM copares switch rates between the front O2 sensors and the downstream catalyst moniters. The catylist moniters are often mistaken as O2 sensors, and they are, but that is not their job, or what they are called.
By comparing the switch rates between the front (before cat) and rear (downstream of cat) the PCM knows if the cat is affecting the exaust, and how much it is affecting the exaust.
If it sees little or no effect o the exaust gases that have passed through the cat, then it decides that the cat is not working anymore, and sets a P0420, or a P0430, depending on which bank it is.
To check this yourself, you will need to bring up data stream on your scanner, watch the upstream and downstream O2 parameters and see if they are following each other closely.
If the cat is working right, you should see a fairly rapid switch rate, probably 5 or 6 times a minute on the front O2, but almost a flat line just above .5 volts on the rear. If the rear is switching often you proabably need a catalytic converter.
You can try resetting the ECM by turning your ignition to the on position (engine not running) and pulling the fuse to your ECM for 30 seconds and then placing it back in. Once the fuse has been reinstalled, start the car and let it idle for 1 min and then go for a test drive.
The engine may stall when you restart it, let is stumble and stall. Just restart it, the ECM is relearning the sensors like it was the first start up the engine ever had then go for a test drive.
This should reset everything and turn your check engine light off, if the check engine light came back on, have it scanned again at Auto Zone, Parts source where they scan free of charge and address the issues the DTC codes points out.
The easiest thing to do first is a visual check of things. Visually inspect the exhaust system for leaks, check the catalytic converter for dents, holes, severe discoloration, and check for a rattle inside. If any of those syptoms are there, the converter likely needs replacement.
Then, visually inspect the downstream O2 sensor (behind the converter). Check for broken wires, obvious faults, etc. If all that checks out, you'll want to check the operation of the O2 sensor. To do that, you'll need access to a scan tool or oscilliscope. Check that the waveform is pretty steady. If the reading fluctuates then the sensor is likely bad and will need to be replaced as mentioned earlier.
Thank you for using Fixya and be safe.

Apr 18, 2010 | 2001 Chevrolet Monte Carlo

1 Answer

Lacking power and making rattle noise


sounds like your cat converter has broken up and is now plugging you exaust.turn off engine crawl under truck and bang on cat converter with piece of wood if it rattles cat is bad. but dont just replace it because something caused it to go bad,number one reason of broken cat is a hard missfire so if runs rough fix that first.number two reason is to rich fuel mixture is it burns the eyes smells bad or has black soot or smoke coming out the tailpipe fix that first also.

Mar 21, 2010 | 2000 Ford F350 Super Duty Super Cab

2 Answers

Have a 1999 Chevy Tahoe, It is throwing 3 codes....PO172, PO420 and PO300 what can cause theese?


* p0172 bank 1 rich. If you have access to a scan tool, I would check the fuel trim and see if engine is running rich all the time. In Chevy, if both banks are too lean or too rich, usually the cause is the Mass Air Flow sensor being dirty.
* P0420 The PCM copares switch rates between the front O2 sensors and the downstream catalyst moniters. The catylist moniters are often mistaken as O2 sensors, and they are, but that is not their job, or what they are called. By comparing the switch rates between the front (before cat) and rear (downstream of cat) the PCM knows if the cat is affecting the exaust, and how much it is affecting the exaust. If it sees little or no effect o the exaust gases that have passed through the cat, then it decides that the cat is not working anymore, and sets a P0420, bank 1 it is. To check this yourself, you will need to bring up data stream on your scanner, watch the upstream and downstream O2 parameters and see if they are following each other closely. If the cat is working right, you should see a fairly rapid switch rate, probably 5 or 6 times a minute on the front O2, but almost a flat line just above .5 volts on the rear. If the rear is switching often you proabably need a catalytic converter. Most likely related to the P0172 code above.
* P0300 multi misfire probable cause. Fuel injectors always seem to get the blame for this one since the there is only a lean condition to one side of the engine.
The fuel injectors on these trucks really have one problem, the poppet nozzles at the end. They can stick either open or closed. If they are stuck closed, then servicing the system will clear up the problem (I recommend that they use the 'top engine cleaner' over anything else). However, if they are stuck OPEN, then no amount of cleaning or servicing will fix the problem unless the nozzles are replaced.
Here is a TSB link to the GM's upgrade from the SCPI to MPI system for your truck. http://members.shaw.ca/betterthanyoutoo/Sticking%20Poppet.htm
Here is also a link to the conversion being done on a 4.3 V6 vortec with the same issues your having. http://www.s10forum.com/forum/f107/scpi-to-mfi-upgrade-kit-324166/
Good luck and try using fuel injector cleaner first to address the issue, Lucas fuel injector cleaner is great for the price for how much you get for it. Just follow the instructions on the bottle and you should be good for a month of injector cleaner when you fill up the gas tank.
Thank you for using Fixya

Mar 16, 2010 | 1999 Chevrolet Tahoe

1 Answer

Po 431 after 2 bran new cats (front and rear) and one new 02 sensor on Mazda 6 2004 V6 3.0L Have misfire on 2 cylinder for about 60km after this reparation but changed it right away! My question : Is it...


Its really hard to say. Some cats arnt as good as others.
A misfire can overheat a cat real easy and use up the chemicals.
If you fixed the problem then clear the code and see if it comes back. Hope for the best.

Dec 24, 2009 | Mazda MAZDA6 Cars & Trucks

3 Answers

1998 saturn check engine lite comes on gives codepo420&po573


Code po573 is cruise control / brake switch circuit A circuit voltage high PO420 catalyst system below threshold, po573 is probably a bad brake circuit / switch problem, PO420 is a bad catalatic convertor for bank 1

Sep 28, 2009 | 1998 Saturn SC

1 Answer

Blocked CAT?? judder on low revs.....


You will not do any damage to the car driving with a stuffed cat.The exhaust has already left the engine and has left the building.No harm to be done.You said the engine goes fine when you stick the boot into it.Maybe not a blocked cat.Its probably engine tune but a hole in exhaust may get it and you going better:)Have a go mate!Hope this helps

Sep 04, 2009 | 1990 Toyota 4Runner

Not finding what you are looking for?
1993 Subaru Impreza Logo

133 people viewed this question

Ask a Question

Usually answered in minutes!

Top Subaru Experts

yadayada
yadayada

Level 3 Expert

76848 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22246 Answers

Brandon Johnson
Brandon Johnson

Level 2 Expert

251 Answers

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

Answer questions

Manuals & User Guides

Loading...