'94 325iS with acceleration issue --- Please help! - BMW Forum

staticvagabond7 · 05-02-2009, 10:33 AM

Hey all, first time posting here.

So, I have a 1994 325iS with around 101k miles on it. About 2-3 weeks ago it starting stuttering/pausing slightly when pressing on the gas hard. it worsened quickly so I brought it to the dealership for a diagnostic. They could see the issue, but had no idea what it was without ruling some things out. They said there were no codes found as well.

So I took their advice and changed my spark plugs (this was the first step they wanted to take). I used Bosch platinum +4s. I did notice my old spark plugs appeared very dirty, seemed as if there was a little oil on them?

Upon changing the spark plugs the car seemed to run fine again for about a day, then the issue came back. This was last weekend. Now its so bad I can barely accelerate the car at all anywhere under 3000rpm, 3000rpm and above the stuttering stops and the power comes rushing back, but until then it shakes, stutters, and loses almost all power. Needless to say this makes accelerating up hills an issue.

Seems alittle louder while idle now but for the post part purrs along. Through some research it seems my fuel filter could be the cause so I plan on changing that this weekend. I'm also going to check the new plugs to see if theres any residue/fluid on them. Any other suggestions would be greatly appreciated!

So to summarize this long winded post.
--- Car stutters and loses power between 1800-3000 rpms. Car vibrates while this occurs.
--- After 3000rpm power comes back and stuttering stops. Will do it in higher RPMs if I really lay into the gas.
--- Does this in any gear.
--- Recent work that may relate includes an oil change, new air filter, and new spark plugs.

Thanks,
Josh

JesterMX6 · 05-02-2009, 06:01 PM

knock sensors? o2 sensor? bad DME?

oldschool93 · 05-02-2009, 09:14 PM

hey man try cleaning the idle control valve, it is an easy process that got rid of the problem for me. there is lots of threads about cleaning the idle control valve (ICV) good luck!

staticvagabond7 · 05-03-2009, 11:33 AM

oldschool,

I had been reading about that and it seemed a tad suspect. I think Im gonna give that a whirl either today or tomorrow and I'll post back with the results. Thanks!

oldschool93 · 05-03-2009, 12:56 PM

good stuff man hope it works

PrInG · 05-03-2009, 02:42 PM

Any time i have problems with my ICV the problem disappears at WOT.. Does the car idle irratically that is usually a sign of ICV problems.. Just spray some PB blaster in the with a qtip and shake it a few times.. Might wanna wait for it to dry before you put it back in.. I've cleaned mine and had it run crappy for a little while before it got flushed out..

staticvagabond7 · 05-03-2009, 10:42 PM

Well 6 hours later (determination or insanity?) and I can't get the ICV back in. Guide I followed didnt require removing the tb/intake manifold which the ICV is underneath, but it looks like Im going to have to anyways now to get the part back in. its about 11:30pm now so needless to say I've given up for the day but I'll be back at it tomorrow evening. Hopefully I'll have results by then.