My 2002 Toyota 4Runner trembles every time I accelerate.

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gitonwitit answered 3 months ago

That's kinda vague, but i'll give it a shot. A vibration on acceleration is generally a drive line issue, which would most likely be a bad universal joint. If it's more of what we call a "fish bite" feeling, then you probably have a misfire somewhere in the engine. On an 02 4Runner an engine misfire, and a problematic catalytic convertor should throw a code, and in turn make the check engine light come on. I have seen times when a vehicle had a miss, but the vehicle didn't know it had one, so the check engine light never came on. I wouldn't think it's a catalytic convertor problem, but I've been wrong at least once or twice before. Good Luck.

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Kurt answered 3 months ago

Hello, well i pretty much agree with the above statement. I first ask if the check engine light is on? and if it is, the very next thing to do is get the codes read from the computer. If you dont want to go to a shop just yet, Autozone will read the codes from your computer for free. Then let me know what code it has. Your description is a bit vague. If it is an engine running problem, several sensors such as TPS, and MAF sensor can cause a stumble. If you have a misfire, it is probably in need of simple regular maintenance in the form of a tune up, spark plugs and wires. a common issue is also the valve covers leaking filling up the spark plug tubes with oil in turn causing a misfire. How long have you been driving it this way? Once a car starts running incorrectly, you should immediately have it checked as you can do a LOT OF DAMAGE BY DRIVING IT WHILE NOT RUNNING CORRECTLY!!! If a car has a misfire, the unburned fuel will travel into the exhaust system, and into the converter where it will be burned, and if you keep driving it that way, the converter gets hotter than it is designed for, it will actually turn bright red and glow as it is about to melt and causes a sever fire risk. Then once the converter is damaged which can cost over $1000 to fix, if you keep trying to drive it that way, you can actually blow up the engine which could cost $3000 plus!! Other things that may cause a tremble, if it is in the driveline, driveshaft support bearing, i wouldn't suggest u-joint because that should be felt any time the car is moving, not just accelerating, maybe the transmission is shuttering, have you checked the fluid to make sure it is full? I have 2 4Runners, one with 212,000 miles and my daily driver has 287,000 miles now. They are excellent vehicles, with not so excellent fuel mileage.

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a1jasong answered about a month ago

I had a similar problem on my '91 4Runner when I bought it...it "trembled" at idle and hesitated around 50 to 55 MPH. I found two problems: 1) There was a vacuum leak in my intake tube due to aftermarket parts being installed incorrectly and it was driving the MAF sensor crazy and 2) Someone had put AC Delco spark plugs in instead of NGK...seems like a small thing, but the plugs caused the hesitation. Lastly, the TPS can be adjusted but a little dab will do you...a small adjustment can make a lot of difference. A Haynes manual will walk you through the adjustment if you have a voltmeter.