Hello!
Back again! I have a 3.0 V6 that has a rough idle and immediate take off shake that goes away once I get going. I recently did plugs, wires, coil pack, fuel injector for cylinder 4 (only replaced 4 because of a CEL at the time) and just replaced both heads. Can’t seem to pin point what is causing the misfire. No CEL hasn’t come on after replacing the heads. Any ideas?

 

CEL will come on if there is a misfire
CEL will flash if its a bad misfire

Does it do it cold or warm or both?

After engine is warmed up let it idle
Unplug the IAC Valve's 2 wire connector
Idle should drop to 500rpms or engine may even stall, either is good if means no vacuum leaks
If idle doesn't change then you have an air leak, and it could be enough to cause idle issues, but not higher RPM issues

Put a can of injector cleaner in the gas tank