When Im just like cruising my car kinda stutters.. and will buck at low speeds.. I notice that I feel what seams to be a transistion normally around 3k but as soon as 1.5k. I have a single turbo so its not boost problems. Just curious if anyone had any ideas?

 

Is this happening just at partial throttle??

If you **floor it** throughout that same RPM range, do you still have the problem, or is it gone???

Well, couple of simple things could be the culprit:

1) your 02 sensor going bad

2) possibly a grounding issue.

Try unplugging the 02 sensor first and then driving at partial throttle for a few mile - If still using the stock ECU [I wouldn't think so with the single turbo...] this will throw an error code, causing your CEL to come on, but no worries...

Maybe you forgot to hook up a ground or two when installing the single turbo??? I'd say a prime canidate is the one that goes from the back of the UIM to your firewall on the driver's side...

 

Assuming you are running a PFC, you may need to add just a little bit of fuel to the cells from P5-P7/N3-N8 (they are all set to 100 with the base 5.08 map). I only added the smallest amount of fuel possible (0.003) to these cells (thanks Rick) and it cleared that up a bit.

It could also be your o2 sensor going bad, as busy13b pointed out. If you have the PFC, you can check your o2 sensor voltages.

 

only at partial throttle and only at those rpms.. I figured it was the primary and secondary injectors switching duty. Ill check the o2 and fuel.