Engine check comes on when in idle. Please help.

[318is_for_me]

Ok, guys I have 1994 318is. Car runs good but recently I noticed when car is in idle it sounds like the engine is about to die. Also when I stop at the stop light the engine check light comes on. I did the compression test 125-125-150-145(it's kinda low and i'm not sure if it is related to the problem). Please help to figure out what causes the problem. I am new to the bmw world so please be patient with me (i learn fast)

[im]

check for vacuum leaks: hose from passenger side of engine compartment valve cover to drivers side..ends at black disc...it falls apart from inside out...can replace with universal hose and two clamps from autopart store..under $15
the black disc. is a positive ventilation valve...the PVC valve...if you are unable to remove oil cap with engine running because of tremendous suction it would be a sign that it is stuck and requires replacement ..about $5..use rag to remove cap..if you are able to remove with engine running the valve is OK.

[Pirate_copy]

Also check the ICV (Idle Control Valve)

Also, get the codes pulled that caused the CEL

I believe Autozone in the US do this for free

[318is_for_me]

thanks, guys. I'll check the hoses for leaks and clean ICV(found a very good diy). I do have a question. Is there a difference between tb cleaner and carburetor cleaner? Everybody I look it says tb/carburetor cleaner, but at the same time I read that someone said not to use the carburetor cleaner to clean ICV.

[318is_for_me]

Ok, guys. Today I replaced the spark plugs and started working on removing the manifold the get to ICV. While doing that I noticed that my rubber boot was cracked. Would that affect my idling issues? I'm going to clean the throttle body and the ICV as well as replace the rubber boot. Could that crack mess up the MAF sensor. Just checking before I order any parts. Thanks

[Pirate_copy]

Yes, it would definitely affect the idle as you will have un-metered air entering the cylinders

[318is_for_me]

Ok, I cleaned the ICV today(it was very dirty) as well as TB. Put everything together. Started the car, idling is much better even though RPM still jump a little (800 to 900). But again I have a huge crack in my rubber boot(ordered a new one). The CEL is on now all the time. Could that be because of that crack? Also I heard that there is a reset you can do by unplugging the the battery cables. Can you please explain how to do that?