Bitt of oil on airfilter, and bad idle

[ChristianDK]

Cleaned MAF on my ´98 230K, and found a thin cover of oil in tube over the MAF - other than that the MAF looked like new. I also found a bit of burned/old oil on the air filter, and in the tubes between airfilter and top!!

My idle fluctuates between 750 - 800 r/pm - should it not be more stable?

Any thoughts would be appreciated.

Going to change airfilter today.

Greetings form Copenhagen!

[Markland556]

Just wanted to chime in and say i have the same problem, my idle goes from about 600-800, it bounces everytime when i have it in gear and am just sitting there. Also somtimes when i start the car the rpm's just drop and the car dies... not too often though. The lights in the car seem to brighten and dim a little too as if it were a voltage regulator problem...

Sorry, diddnt mean to hijack your thread..:p

[ChristianDK]

bump. Sorry :)

[Proven Guilty]

Originally posted by Markland556
Just wanted to chime in and say i have the same problem, my idle goes from about 600-800, it bounces everytime when i have it in gear and am just sitting there. Also somtimes when i start the car the rpm's just drop and the car dies... not too often though. The lights in the car seem to brighten and dim a little too as if it were a voltage regulator problem...

Sorry, diddnt mean to hijack your thread..:p

that's normal for the low rpm idle range to have the lights dim. it generally varies because of the speed of the alternator belt changing with the engine rpm - it seems that once you're over the 1200rpm range, the lights wont dim at all for me, because the "juice" is more consistent.

i would start to suspect a voltage regulator if you were having problems with the sun roof, the speed of the windshield wiper was inconsistent, or flickering dash lights. when my voltage regulator was failing, it actually allowed an over charge of the battery, rather than deprive it.

for both of you guys, it sounds like it's one of 3 common things once you get over the 80k mile range:
-MAF/MAS/AMM
-Plugs
-Coils

the thin coating of oil in the intake tube seems common to me, as it's probably a result of the recirculated air from the valve cover area. I would only be concerned of excessive amounts (like you would see wet oil on the bottom of a dipstick) in that tube, as it could hint to leaking supercharger oil (much bigger problem).

Also, do you run a stock filter, or do you have an oiled service filter like a K&N brand?

[ChristianDK]

Thanks a lot.

Very helpfull. If it was leaking from the supercharger - how big a problem would it be? Just curious.

Just installed a K&N - no difference in idle. Still not that stable. Have ordered Iridium plugs to see if they will help.

Greetings form Denmark.

[Proven Guilty]

i would try cleaning the MAS again when you do the plugs. I also run Iridium plugs, and they seemed to help response ever so slightly (my guess would be 1hp / 3lbs of torque) but didn't really affect gas mileage in any way.

it might just be time to replace it.