I have a 97 tahoe 4x4 egr motor.
In this cold weather we have had, it starts ok for old spark plugs, but it has a slow idle,. and misses on a couple till they warm up usual bit of smoke then it clears once shes popping all 8.
BUT,..for the first up to a minute -ish, i have one hole that sounds exactly like it has a stuck open injector, my friend was listening and he was alarmed and started with "its got a rod knocking"
Give the motor a minute or so and the rap/fuel knock dies slowly down untill it sounds all systems normal, except for the low idle. Oil pressure is good and consistent hot idle is 35 or so. Engine is you garden variety happy little 6.5 when it up to 180 deg or so all sounds are normal. I did unplug the temp sensor to see if a bit more timing would help or maybe trick the ecm into raising idle but it did rattle a little more but no rpm change.
Conjecture what the problem might be?
Thanks for your thoughts.