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Followup To
Question -
Hi,
I have a 93 Toyota 4 Runner 4wd with a 3.0 engine and 5 speed,and 140,000 miles. A couple days ago it started sputtering at 65 mph around 2700 rpm. I noticed it only does this in 4th and 5th gear at 2700 to around 3000 rpm, and not in any other gears. I also noticed that the idle is a little rough, but the vehicle still accelerates well. I changed plugs, wires cap and rotor a couple months ago, I change the fuel filter yesterday, and checked the spark plug wires to make sure none of them are loose. I checked the timing and the timing is ok too. I have thought about changing the coil, but I don't want to just start throwing parts at it.
Answer -
Before spending any more money on parts I recommend testing the engine to make sure it's basic mechanical functions are good, this means having the cylinder compression checked and having it checked for a blown headgasket, these engines had headgasket problems and there is stil a "recall" in effect, you need to contact your local toyota dealer so they can check the VIN# and see if it applies to your vehicle.
Hi Ted,
Thanks for the information. While pulling spark plugs out to check compression, I found a spark plug that had backed almost all the way out. I found this to be the cause of my problems and the 4 Runner runs great. I changed the plugs about 2 months ago and have about 3000 miles on the vehicle since the plug change. I have owned the vehicle for about 3 years, and the first thing I did when I bought it was give it a tune up. It wasn't long after that tune up, I had a plug come out while going down the interstate, and now 3 years later a different plug has almost come out. Is it possible that the plugs are not seating properly in the head, a co worker says he has a tap for spark plug holes made by Snap On that also cuts the seat for the washer on the spark plug. He has offered it to me to use, but I'm a little leary of using it. I was wondering what your opinion is on it. I feel like I won the lotto by finding the loose spark plug and I won't have to spend any money or deal with the dealership to get it fixed. Thanks again.
AnswerIf the threads in the cylinder head are damaged they should be rethreaded with an appropriate tap, it's possible that the affected spark plugs are not seating in all the way into the head because of thread damage and then work their way loose, a properly tightened and seated spark plug will not unseat or loosen, if the threads are ok, make sure all spark plugs seat all the way and compress the sealing gasket, you can torque them to about 16ft/lbs.
