Hey Ya'll,

First of all, I did some searching. I just am curious to what most of you would do to determine where the stumbling is coming from, spark or fuel.

When cold and in open loop, I have no problems. Feels great. When the engine warms up and goes into closed loop, heated 02, the car has a mild stumble/hesitation off idle and doesn't really let up until about 2200 rpm. Tonight I played with the low rpm VE table, added some fuel, and it got a little better. Then I added some timing in the same RPM and MAP area and it got a little better still.

I have also had a slight surging when in part throttle cruise since the new engine. Its not bad, but I don't like it. I feel it at about 2500 rpm. If I cruise higher, 2800+, I don't feel anything.

What are some thoughts? As for the stumble, I think I am lean down low because I stay out of the gas for now, since its new and untuned, and I checked the plugs today and they look a bit lean. They are pretty new, changed Sat. afternoon.

Thanks in advance...