SR Drivability Question: Stutters right before hitting boost.

[2_Liter_Turbo]

Well, when I give it gas it will kind of stutter, and cut out a bit before hitting boost. Then it will have plenty of power after it goes into boost. Also, if I cruise at the same RPM's (all happens between 2k-3k) it will do the same thing. The only thing I can think of that would cause this is a vacuum leak or something, but I can't seem to find any. Any suggestions?

[Nismo_Freak]

If you aren't WOT it could be an 02 sensor causing the stumble.

Double check your timing to make sure you aren't picking up momentary knock as a result of the timing being advanced.

Check the TPS for correct voltage parameters.

[ILikeMy240sx]

I had the same problem when my IACV was not connected. I have a greddy intake mani so I used custom made cold pipe so the line that goes from the cold pipe to IACV had to be plugged.

When I was between 2~3k RPM and tried to accelerate, I would get a bit of stumbling depending on how much gas I was giving. More gas -> more stumbling but once it went past 3000 it was fine.

Yesterday, I finally got a cold pipe with a nipple for that vac hose and connected the IACV. And now it doesnt do that anymore and my car starts up when its cold (finally).

Vac leak might be an issue as well. I'd test that as well.

[2_Liter_Turbo]

If I hit WOT, it doesn't do it, only at partial throttle (anywhere from 10% to 80% according to my SAFC2). That and it starts great in 20 degree weather. The o2 sensor I used came off of my clip. The wires looked new, but that really deosn't mean anything. I am going to test the TPS first, then replace the o2 sensor, and see what happens. If those don't work, I'll see what I can do about the AICV. Thanks for ideas guys. I'll post up any results I have.

[brandon clifton]

Did you ever find a solution to this problem? Mine is doing the same thing- after I drive around for 15 minutes or so and the car is completely up to temp, it studders and hesitates around 5% throttle, but at idle and on boost it pulls fine.

[Hijacker]

I would look at your temp sensor since it's happening at operating temperatures.

[2_Liter_Turbo]

Lol, that was 5 years ago! Hella old post! Anyways, if I remember correctly, it was either the coolant temp sensor (ecu one of course), or one of the hoses that was connected to my IC pipe had a crack in it. I think it was the coolant temp sensor for this time though. I had an issue twice when my motor was stock that made it do this. Good luck on finding out your issue man.