Hello!
I have a 2000 Z28 with a LS1/LS6 T56, with a cam (don't know which one installed by a previous owner), ported tb. When I bought it, it had longtubes and since then, went back to stock exhaust manifolds and cats for state referee in CA. Even before all of this, the car had this stumbling on a warm/hot startup. Cold starts are great, but this stumbling on hot starts bothers me. Stumbles like it wants to stall out but after a few seconds she finds her idle and sits nicely from there. The car was tuned prior to me taking ownership. Car idles at the desired idle 896rpms perfect at about 21-23 degrees advance.
A few things I've dug in on is increasing the startup frictional airflow and decay. What it was set to before was 3.50g/s around 140f+. On a hot startup, I have managed to get it to start fine when ECT was around 176f+ and startup airflow upwards to 5.45g/s or a bit above. and the cold start I leave untouched, but between the cold and that hot start temp, I still get that damn stumble.
A new beginner to the tuning and learning day by day.
Should I be playing with the startup frictional airflow or may my problem lie elsewhere?
I can upload my current tune if anyone wants to dig in on it.
Thanks.