300zx shaking at low speed/just sitting there

Question

my 90 300zx shakes when im just sitting there,even if its right after i start it up. and it shaked when im stopping and going at low speeds. any clue what could be wrong. please help.

Answer 1

easy...don't go slow!!!  duh!

Answer 2

I would replace spark plugs, Clean or replace air filter (depending on the type) and clean Mass Air flow sensor/meter. Also check vacuum lines

Answer 3

If it shakes while stationary it is not a problem with the drivetrain (transmission and wheels). It may be that one of the spark plugs is not firing. This would be accompanied by a rougher sound from the engine (kind of a chug-a-chug) and could be caused by a bad spark plug, a bad plug wire, or a bad distributor cap. If it sounds like it is running as fine as usual and not one of the above problems then it could be damage or looseness of one of the rotating parts of the engine like the Flywheel, alternator,or air conditioner compressor. Worst case would be broken or loose connecting rod or damaged crack shaft, which is usually accompanied by a knocking sound that generally gets worse with acceleration (very bad news $).

Spark plugs and distributor caps are cheap and easy to do yourself. Try that first. Plug wires are more money $30-$100, and are also easy if you replace one at a time.

Good luck!