I have a 99' Silverado with a 6.0,cam,headers, exhaust. My VE and MAF tables are dialed in and my idle in park/neutral is excellent. Now the "but" when I shift into Reverse or drive the truck idles fine for a moment the iac starts to ramp open all the way and the timing drops to 3*. For the life of me I cannot seem to find the culprit!!
Someone take me to school please!!
Perf_0002.tunCrazy truck.efi