I have a 06 4.3 that on cold start up wont idle for the first 5 seconds without stalling out. If i hold the rmp up above 1000 for 5 seconds its fine. What on these engines (on cold start) the extra fast idle rpms? I dont have any other idle problems at all. Once it been running for 5 minutes or so it will start and idle perfectly. Ive cleaned the thoottle body (wasnt dirty at all 55K on engine) mas air was clean as can be, no vaccume leaks, clean air filter. No trouble codes at all. Any help???