Hello everyone, I am currently trying to fix a rough Idle on my 2002 3.9L V6
Dodge Dakota. During a recent scan I noticed my Fuel Trim Banks 1 and 2 Long Term is running rich at -10.16 and my advanced timing at Idle is jumping from 12.5 degrees to 20 at times. Truck has new plugs with correct gap. New plug wires, distributor cap and rotor and new IAC. TPS tested good. MAP sensor is good. Ignition Coil is good. No vacuum leaks I can find. Fuel rail pressure is good. What could I be Missing? Could it be the Pickup Coil on distributor or the crankshaft sensor?

Have you looked down into the intake manifold through the throttle body by holding the throttle wide open (engine off ) to see if oil is puddling in the bottom of it ? if you see oil then the pleneum cover gasket is blown and needs replaced and it could very well be causing the rough idle , rich running , and erratic timeing that you have been experiancing .

PonchoRob, Thanks for the info. I will check that next.

Well, I had a look down into the manifold and it is clean. No Oil. Maybe i have a bad injector.

2002 Dodge Dakota 3.9L V6 still running rich. No vacuum leaks. New o2 sensors, IAC, TPS tested good, MAP sensor good, New cap and Rotor, new plugs and wires and New Crankshaft sensor. Fuel rail pressure tested at 49psi and within specs. Vacuum test below throttle body tested good. Compression on all six cylinders good and within specs.

While watching my Long Term fuel trims on Bank 1 and 2, they seem to slowly
increase on the rich side the longer the truck idles. It will go from -5.63 to upwards of -30. When I hit the accelerator they tend to drop back down but only to around -10 or so. Then they start their climb once again. I know the truck will run rich when cold, but this happens after the truck is warmed up at full operating temp.