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I have this 1990 Toyota 4Runner 3.0 liter engine. The engine has been having rough idle for a while and I already replaced the spark plugs. What else can be next? I'm not sure what else to replace so the idling can stop. When I turn it on when it's cold, it idles fine, but once it warms up, it drops down and starts to idle roughly. Please help me out with this situation. Thanks!

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At this motor's age the vacuum lines need replacing, new air filter, and see if it wants high test fuel.

Posted on Nov 25, 2013

  • 7 more comments 
  • Efrain Delgado Nov 25, 2013

    Okay I replaced the air filter already. And well today when I turned it on, it seemed as if it was Choking and almost wouldn't want to turn on. Then it turned on but lots of white smoke comes out. I'm not sure what it can be. And also alot of water came from the exhaust tail pipe. I already cleaned the Egr valve but now sure if it was stuck open or not

  • mike kirschbaum
    mike kirschbaum Nov 25, 2013

    Check the radiator. If it is low, and the same color water is coming out the tailpipe, you may have a bad head gasket. A compression test will tell, before you go tearing the motor apart.

  • Efrain Delgado Nov 25, 2013

    Yea I though it would've been that. But does that make the engine idle roughly?

  • mike kirschbaum
    mike kirschbaum Nov 25, 2013

    yes. At low rpm the leak can affect combustion. At higher rpm the leak may not have a chance, and manifold vacuum is lower.

  • Efrain Delgado Nov 25, 2013

    Alright thanks! I'm going to buy some bar's head gasket repair to see if that helps.

  • mike kirschbaum
    mike kirschbaum Nov 26, 2013

    Yeah, at 23 years old, you can't hurt this motor any more. Shop around for a replacement motor with low mileage. Sometimes it's cheaper to replace the whole motor, and you may get spare starter and alternator, etc. Swapping a motor may be cheaper than a rebuild, check it out.

  • Efrain Delgado Nov 26, 2013

    Yea that's true. I just recently also replaced the tranny on it too. So I'm going to start looking at salvage yards for a used engine. Any tips on what to watch out while I look for engines? How to know how an engine looks or isn't working?

  • mike kirschbaum
    mike kirschbaum Nov 27, 2013

    A good motor will be naturally clean, not pressure washed or steam cleaned.

  • Efrain Delgado Nov 27, 2013

    Alright sounds good. Thanks!



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Posted on Jan 02, 2017

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SOURCE: 2001 v6 escape rough idle when cold

To update my earlier repair on the 2001 6 cyl Escape: When cold, and when the ignition was turned over but no accelerator pressure given, the rough idle finally returned the P0303 code again when the check engine light came on indicating that it wasn't caused by the plugs or the coil. FYI, I had replaced the intake manifold gaskets during the original repair and just prior to that I had replaced the fuel filter which was very dirty (I cut it open to see).

The repair manual referred to fuel injectors as a possible problem. I have run three tanks of fuel using different injector cleaning products and am very pleased with the results. Cold starts are much smoother and I am unable to coax out the P0303 code or any other code.

My opinion, change the fuel filter, use a fuel injector cleaner for a couple of tanks, change the plugs if the problem still exists. The coils were not the problem on my vehicle.

Posted on Mar 09, 2009

  • 80 Answers

SOURCE: Rough Idling, start-up early morning, until engine heats-up

this may be a sticking air flue meter take a matchstick .and push it into the hose this will let more air in if this works change the air flue meter

Posted on May 04, 2009

  • 6 Answers

SOURCE: 2000 toyota 4runner pulling a random misfire in

try a new crankshaft sensor not hard to change 2 bolts and a wire

Posted on Jul 30, 2009

  • 12744 Answers

SOURCE: O2 Sensor Problem?

yes an o2 sensor can cause those symptoms so can a minor vacuum leak --bad ignition wire -clogging fuel filter --sticking egr valve etc.

Posted on Mar 01, 2010

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SOURCE: 2000 beetle cold start rough idle until it warms

Could be the fast idle sensor check to see that the vacume line is hooked up properly.

Posted on Mar 17, 2010

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