Question about 2000 Toyota 4Runner

1 Answer

Hello. my 2000 4runner v6 has been running rough. when i start it, it runs fine untill it warms up. then it begins to miss. have replaced spark plugs, and battery but didn`t make a difference. diagnostic tool says engine misfire.

Posted by on

Ad

1 Answer

  • 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.

  • Master
  • 1,586 Answers

Change your oxygen sensors - they're responsible for feedback that the computer uses to determine the air/fuel mixture. They usually are good for about 60k miles and then start to go downhill. When they get to a point that the computer won't trust them, it ignores them and runs on preprogrammed fuel maps that run excessively rich (too much fuel) to safeguard the engine. You've probably seen a decrease in fuel mileage as well. And the O2 sensors have to be up around 900 degrees before they'll work - the car ignores them until then. That's why you run fine after a cold start but run rough once the car is warmed up.

The O2 sensors you want to change are in the exhaust system between the engine and catalytic converters (the "pre-cat" sensors). There are O2 sensors after the cats as well, but those are used comparatively to determine how well the cats are functioning. The primaries are the ones used for fuel mixture. If it's been this way for a few weeks or so, I'd put new spark plugs in as well - rich fuel conditions can foul them and contribute to the rough running.

Posted on Dec 09, 2009

Ad

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 there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this 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.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

1 Answer

4.6l. After warm-up, why does it run rough with missing?


Could be spark or fuel.
Weak or worn spark plugs, weak coil, dirty injector, and so on.

Jan 05, 2016 | 2001 Ford Mustang GT

3 Answers

Starts and runs fine.....rough runs, when you restart after warmed up


Sorry - I didn't see the vehicle information the first time.

Let me research this - i will get back to you soon.

Aug 03, 2014 | 1999 Subaru Legacy

1 Answer

95 VAN SPORT STARTS FINE UNTIL MOTOR STARTS TO MISS THEN LOOSES SPARK


I Think Your Problem Is Still With The Fuel Supply,Have You Changed all Fuel Filters,Follow All The Fuel Lines Make Sure There Are No Kinked Fuel Hoses,Some Times You Find Small Filters In The Top Of The Fuel Injectors.
Hope This Helps

Apr 06, 2013 | 1995 Pontiac Trans Sport

1 Answer

I have a 2001 mercury sable with a 3.0 dohc engine. When you start the engine it misses and runs rough till it warms up, it then runs fine


Run the codes,change spark plugs,clean the MAF sensor and always make sure to replace a fuel filter every 30K miles. don-ohio

Dec 31, 2012 | 2001 Mercury Sable

1 Answer

Buick 97 lesabre, runs rough when warm


Buick 97 lesabre, runs rough when warm

Jan 25, 2012 | 1997 Buick LeSabre

1 Answer

1991 corvette-engine runs rough then cuts off


could be vapor locking, losen up the fuel cap and see if that helps if so then replace it!!!!!!
and chane the fuel filter also

Jun 11, 2009 | 1991 Chevrolet Corvette

1 Answer

Rough idel when cold start


if u have a damaged plug it can be running on 1 less cylinder ,it will idle very rough,change it!

Mar 26, 2009 | 1993 GMC Safari

1 Answer

1991 toyota 4runner v6 auto rough start


Possibly a leaking head gasket. Water/antifreeze seeps into the cyllinder when it cools off, and then it won't fire properly until the coolant is blown out the exhaust when you start it. Let it warm up with the rad cap off. If you see bubbles continuously coming up to the filler hole, you have a head gasket problem. Do you have to add coolant monthly, or weekly?
If you're lucky, it could be just a spark plug that doesn't want to do anything until it warms up, or it could be a valve.

Mar 14, 2009 | 1991 Toyota 4Runner

Not finding what you are looking for?
2000 Toyota 4Runner Logo

670 people viewed this question

Ask a Question

Usually answered in minutes!

Top Toyota Experts

Marvin
Marvin

Level 3 Expert

83557 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22393 Answers

Jeffrey Turcotte
Jeffrey Turcotte

Level 3 Expert

8841 Answers

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

Answer questions

Manuals & User Guides

Loading...