Stumbling on Cold Starts

[thehata1]

Gents,

I have an LQ4/4L80e that I am finishing up. Brendan @ lt1swap programmed the ecm for me. The first few times (first couple of weeks) I cranked and ran the engine, no issues. The last three times I've cranked the truck on a cold start, it stumbles heavily and didn't start first time two of those attempts. After the first time it did it, the next day, I cycled the key a couple of times to make sure the fuel was not bleeding pressure down. That did not help. After the truck starts and runs for a minute, all subsequent attempts to start are fine.

I have not road tested the setup yet. All attempts are in the garage.

Any thoughts?