i just replaced the motor that was blown in my truck its a 3.0 flex fuel and put the same motor in it. itll will start fine but right when u tap the gas it shakes a little like a miss fire or something it does seems to run fine its just when you tap the gas pedel. anyone know what might cause this?

 

Need more info - year of truck, year of engine swapped..

 

Yes, more info would be helpful. By the way, Fred from Rogue Performance ("Fredness") is THE expert on 3.0's.

Could be something with the MAF depending on the year. 1998's have a limp mode that might help you diagnose it. Unplug the MAF and see if it runs better. If it does, chances are you need a new MAF. My daughter's 98 was like that and I ended up replacing the MAF on hers.

 

Normally there are issues like this when FFV PCM meets non-FFV injectors>