Vibration 2002 Mazda 626 4 Cylinder

I have a 2002 Mazda 626 with 130,000 miles, that has a vibration when in park or neutral at idle. My mechanic first tried a tune-up changing the spark-plugs and leads. Then he changed all five motor mounts. Failing that he change the motor mounts again to no avail. He has pulled and checked the air conditioning compressor and he has checked every pulley, belt or cable.Then he then sent the car to a “special shop” to check the crank shaft and journals. Well the motor is “good” and that didn’t seem to be the issue. He then replaced the harmonic balancer and that didn’t do anything and then finally changed and balanced the flywheel. Yesterday he gave it back to us with the timing advanced so it wouldn’t idle but thrusting us into the back seat when shifting from park to drive. My mechanic is at his limit and I don’t know what else to do with the car as we like it and no one seems to know now what to do.


Christopher Brooks

Claremont, California

Cars normally run rough for 2 main reasons; 1) they don’t get the right spark, or 2) they don’t get the right fuel/air mixxtue in each cylinder. I’m surprised the mechanic did not check out the fuel system (which is oinexpenssive to do), including the injectors.

There could be several causes, of course, but I think the mechanic acted much like a quack doctor; if that does not cure you, maybe this will! Your mechanic was likely at his limit before he started the work. The mechanic coul also have re-installed the timing belt incorrectly, which would cause the engine to run rough.

You really have no choice to take all the documentation of all the work done and take it to a competent mechanic, who will first do a proper diagnosis (like any good doctor), and then proceed to fix what was wrong.

Good luck!