m60 engine surge

[3bimmers]

my 94 530i engine surges when i let off the gas. at idle it surges up in rpms several times (usually about 3 or 4 times) then settles down to normal idle speed. the engine runs fine until i let off the gas and it will surg again .otherwise it runs great has plently of power and doesnt appear to burn any excess fuel or oil. any ideas what is causeing the surging?

[tim]

Basically normal, but if you want to hunt it down: first check for air leaks on the afm boot by taking it off and really checking, next clean the throttle body and ICV valves w/ carb cleaner. If you're not throwing a code, forget about the o2 sensors. Failing all that, maybe plugs. My idle really smoothed out when I put in an EAT chip, and it did not have any of the aforementioned issues.

[Unregistered]

My M60 engine (1994, 530 Auto) has always behaved impeccably -absolutely smooth and never missing a beat. However,during the last week the tickover has become very slightly "lumpy" and occasionally when, ticking over, the engine will suddenly stop . It starts again immediately but I sense a slight hesitation when moving off. At all higher engine speeds it feels fine.
I have cleaned the plugs which look as new and used plenty of WD40 around the HT units and the ECU connections.
There is no sign of water or corrosion on the electrics and the only thing I noticed was a small quantity of oil collected in the spark plug recesses. (oil consumption is virtually nil)
I feel that one or more cylinders are mis-firing at low revs thus causing the slight shudder that is not normally perceptible, though the tickover speed is very steady at 600rpm. How do I isolate the problem ? Is the only answer to visit a main dealer with a diagnostic facility ?

[632 Regal]

my car (nice choice I might ad) had a slight miss when I got it. I went through it and found a small leak at the intake, no fix. then I bought new injectors, plugs, coils and finally fixed it by replacing the rubber plug boots. I would start with the boots first...not last like I did.

[Unregistered]

Thanks for the advice - I will start by relacing the boots - I guess they just pull off the coil units ?
Tickover is what we Brits call "Idling" :-)