guys,

3.9L, recent tune up, new coolant temp sensor, new MAP sensor. Condition still prevails. Plugs are black...and i dont' know where to go.

Bad ECU???

Evan

 

Is your fuel pressure in the fuel rails proper? Have you recently replaced ur O2 sensor lately? ... Just some ideas off of the top of my head. I can't really see the ECU going.....

 

BAD ECU (doubtful)

Think basic, probably somethin stupid. If the plugs are black with powder, then you are probably running too rich. Either injectors are stuck open constantly dumping in fuel or like previously stated, its probably an O2 sensor. They are about $40 at AutoZone.