I have a 1990 with a 3.9 5 speed. It starts right up and idles fine but it intermittently bogs down and runs real rough when accelerating and driving along like it can't breathe with no power. I thought it might be a bad catalytic converter and changed that but it didn't help. When it happens, the check engine light comes on and resets itself after the truck is shutoff. I have another 88 parts truck that ran great before it was parked so I can swap parts to experiment. I also have an exhaust leak on the drivers side of the engine somewhere, I don't know if that's related or not. I just got this truck running recently after it sat for several years with the motor torn apart so I don't know the history. The bogging is getting worse, I've driven it about 100 miles since I first got it running. Is there a way to check codes? I have access to a OBDII code reader but it has a different input plug then this Dakota.

 

It could be anything. First check all wires, hoses ect. Next see what the codes are. You can read them easily by turning off and on the ignition switch 3 times. For the list of codes check out the FAQ in this section.

The 90 will be a OBD1. The OBDII does not work for it. You would need an OBD1 with a Dodge specific connector.