For some reason when I accelerate slowly in 1st gear (most noticeable in that gear anyways), right around the 2000 RPM mark the engine seems to stumble. It feels as if I lifted my foot off the gas pedal for a half a second, and then got back on it. I think it happens in other gears too but a lot tougher to notice. It is quite easy to replicate the problem as it happens about 50% of the time.

It makes driving in traffic smoothly nearly impossible, and is embarrassing when I have passengers in.

I was thinking spark plugs are on order soon, but any clues as to what else it could be??

Thanks in advance

 

Verify that it happens in higher gears. Maf or vacuum/boost leaks most likely.

 

Thanks Tim.
At 2000 RPM there is no boost, and the car pulls like a beast when there is so I don't think its boost related.
I was going to clean/test the MAF when I find some time.

 

A boost leak will let in or out unmetered air. That can create a lean condition. At 3000 the high lift and cam retard kicks in, you feel that cruising around..

 

Could it be the VarioCam? When VarioCam kicks in/out it can feel like a momentary engine stumble. For me this is noticeable between 2750 and 3000 rpm only when I'm using light throttle to maintain speed. I've learned to either cruise at a lower or higher rpm to avoid that stumble.

Ed

 

sigh, i'm having the similar problem, but more of a miss-firing issue though, Tony @ EPL is doing the tuning on my 24/18g setup right now so i'll have to wait and see how he can solve the problem since it only happened after the turbo upgrade / software upgrade process.

 

How many miles since your last change of plugs?

 

I really don't know when the last change of plugs was, as I just got the car recently. Its not much money to change them out though so I figure I should do that anyways. So plugs, clean MAF and then I'll see if it still occurs (hopefully not!).

 

take off the air box and smoke check the intake track.