same dang problem!

[iturboh]

I have 94 318i convertible and the idle on the car stays a little over 1000, sometimes a little higher but it does come down and ends up idling at 1100-1000 and OCASSIONALY, it goes down to where it is supposed to be at which is 800. Once it's there yiy starts shaking a little and idle gets really rough. Sometimes it drops to even 400-500 rpm then shoots back up 1000+

Last time I checked the engine light I believe the code was 1222 so I replaced the oxygen sensor yesterday and it still has the same problem. On the cold morning the idle does go to 800 but it is still rough.

Any one know what's wrong or have a similar problem?

I really hope its not the MAF... I realllllllllly hope its not that lol

[JDStrickland]

Have you looked at the throttle linkage to be sure it is not hanging up?

When you press the gas pedal, it pulls a cable -- EXACTLY like a brake cable on a bicycle -- that in turns opens the throttle plate. The throttle plate has a spring so that when you release the gas pedal, the spring pulls the cable back to the original position. If the cable hangs up, the throttle does not close fully, and the idle speed is high as a result.

Drive your car around the block and when the idle speed stays high, go home and open the hood -- or pull into a parking lot and open the hood -- and manipulate the throttle linkage by hand to see if you can determine that something is blocking the return. You want to look for kinks, frayed cable, dirty cable -- DO NOT USE WD40 TO CLEAN THE CABLE -- those sorts of things. Don't forget to consider the condition of the gas pedal itself.

You could have trouble with the expensive stuff, like the MAF, but you really want to look at the cheap stuff to fix first. The general rule of thumb is that the cheap stuff is usually the problem.

[iturboh]

Will definitely try this right after school in an hour!

It closes normal so that can't be the problem. Any other possible culprits?

[iturboh]

is there any youtube vids or step by step processes to cleaning the MAF? the search on this website is not cooperating with me at all

[Marv17]

I had similar issues on my m44.
I would first check out the end links of the throttle cable. See if the rubber holding the cable in place is ripping. It make mess with how firm the cable stays in place. Found a metal replacement that'll last years if you're interested in the same thing. I can provide you with a link.
Next i would look into the crank case valve. It looks like a pancake looking thing behind the intake manifold. The internals break as time passes especially if it's never been replaced. Easy fix. About $70 bucks for it. Clean the MAF properly. Check if the ICV is cleaned out. Soak it in carb cleaner for a hour or two. Then inspect all intake hoses to see if any tears or cracks.

That's all I can think of. Good luck.

[JDStrickland]

Code 1222 is not the MAF. That code means the O2 Sensor is running up against the lean and/or rich limits.

You need to be looking for intake leaks -- which are vacuum leaks -- that are allowing extra air into the engine. If there are no leaks, then your issue is the O2 Sensor.

You said that you replaced the sensor, did you use one that plugs in, or did you have to splice it? If you spliced it, then you have to go over your work. An O2 Sensor is probably the worst thing that ever came with a splice kit. These things work on very small voltage and very limited current, and a bad splice can render the circuit a complete fail. Were you careful to not contaminate the tip?

[iturboh]

Alright I'll try cleaning all the parts associated with the idle and hopefully that'll do it, where would all the parts be located such as the maf and icv, and what are the process of cleaning them? Sorry for the noob questions!
I tried using the search on here but it just keeps saying loading results and never does.

The new O2 sensor didn't get dirty or damaged, just came out the packaging and into the car, the old one was completely black.

[Marv17]

Look on the 318ti.org. They're all a nice group of ppl. If you search there or post up they'll help you out (just ask nicely). Take different pictures of the engine bay so they can help guide you. some pics are there already to help you locate things. Or you cano look up on realoem.com to find the parts.
But start with the intake boots.