Reaplaced FICM now I have new code

[BUICKpowerSIX]

So like I said replaced my FICM and the first day driving I got p0305 and later that day p0300. The truck finally starts in the cold which is nice since its been dropping in to the teens here in michigan lately. I still get that "shutter" when the converter is locked up and seems to be the worse ant about 55mph (guessing due to where the engine is in the powerband and the inertia is not as fast as 70ish.)

Taking the truck into the dealer hopefully fri to have then hook their machine up to it. Any ideas what to do for now to try to diagnose it myself?

 

[Dalpilot]

Its a bad injector.....won't show up till it actually fails. Mine did it for nearly a year. It was a PITA.

 

[BUICKpowerSIX]

would you put your money on #5 injector? I have heard or pulling the plug on it but if it is intermittent or not as bad at times how will I know that is the right one?

 

[PSDPlayer]

P0305. Cylinder number 5 misfire. The P0300 for random misfire means it saw them dropping out all over.