rough idle

[cm2590]

im getting a rough idle but no check engine light...anyone have a idea of what it can be...i check and replaced vacuum lines so that part check out ok..idle control valve maybe? or 02 sensor

[flyfishvt]

plugs would be first on my list. Check the boot between the MAF and throttle body. The back side of it is well known for cracking. Check the connection where that boot meets the MAF and make sure the clamp is tight. There is a small vacuum hose that runs from the underside of the intake manifold to the Fuel Pressure Regulator on the rear of the fuel rail. Mine was broken in two.

[spoonerDee]

Idle Control Valve is usually the biggest culprit with the e36. Clean it out, if it has never been done I'm sure its all kinds of gunked up.

[DrinkCoffee]

Also try MAF cleaner, since it is so cheap.

My bad MAF causes a rough idle (and fast idle).

[hursh328ic]

don't forget those hard to get to vacuum lines under the intake

[cm2590]

well i clean the idle control valve even tho it really wasnt that dirty ...checked all the vaccum lines for leaks and the boot that connect behind MAF sensor and im still having a shitty idle...it the morning it idles fine for a few seconds then idles like crap when it warms up...i unplugged my MAF sensor and the idle went back to as smooth as a whistle...kinda weird thing huh?? as of right now im running the car with the MAF sensor unplugged for now & havent had any problems so far....buying a new MAF sensor is still on my to do list tho

[DrinkCoffee]

Yeah, if it runs better without the MAF, then the MAF is most likely the culprit.

Check junkyards; used MAFs are 50$ around here...

[E36B1MM3R]

MAF sensor was bad on my car and it idled terrible and would load up on fuel which made it hard to take off.once changed my car ran like a champ again..thats probably your culprit:devillook.

[cm2590]

akright ill hit up the junk yards....thanks guys

[flyfishvt]

Before you buy another MAF you need to clean the one you have.

MAF test is as follows: Unplug the MAF, if idle improves clean the MAF and plug back in, if idle is still rough, clean it again, if its still rough, replace it.

don't run the car very long with the MAF unplugged. Your fuel/air mix will be way off. Its ok for a short time but its not a good idea if you don't have to.

[cm2590]

what should i use to clean it with its a bosch hot-wire MAF....if i was to leave t off totally what problems will my car run into besides bad fuel economy? i duno if it make a difference but do you think my turbo damage my hot-wire MAF? should i upgrade to a different MAF such as swapping another totally different MAF?