Question: Shaking and jerking car, RPM going up and down

Lately, the car seems to be jerking and shaking and the RPM goes up and down while stopped at the lights or stationay. The jerking lessens when i put it into neutral. It is a automatic '94 316 model BMW

Only on low RPMs? or always?
It may be spark plugs or cables....

RPM moves up and down only when the car is stationary i.e stopped at the lights. sometimes when the RPM goes up n back down quickly the car jerks forward a bit.

few things..... from my experience. il go from easy to not so easy.

a) cracked in your air intake pipes.(check for cracks around idle control valve part number 6 on link) the cracks can take in unneccesary air and messing with the fuel - air ratio. which happened to be a problem for me.
http://www.realoem.com/bmw/showparts...81&hg=13&fg=15

b) the idle control valve could be faulty.(i bought new one and wasnt the problem for me!!)
c) o2 sensor http://www.pelicanparts.com/bmw/tech...-O2_Sensor.htm

d) gunk in your engine throttle bore
http://www.2carpros.com/how_to/how_to_tune_up.htm

e) check your plug leads for cracks, they might be arcing off the engine head.


to date i fixed all these but my car still idles irratically sometimes so i still haven't got a complete fix but its ALOT BETTER THAN IT USED TO BE
Steve

thnks alot for that. i'll take a look at those things. update ya on any improvements!

Could also be your Intake Temp Sensor. Mine is playing up too and just keep forgetting replace it

Get your codes pulled, you may just get an error code if your car supports it. if it doesn't work after a few attempts, you will need to get a scan tool or get a garage/Autozone to pull them for you - http://www.forum.edirty6.com/showthread.php?t=65 (top post)