The OBD1 computer got fried on the 1994 12 valve Cummins, so we try out some DIY repair techniques on it. Bad capacitors are a common problem with older electronics like this, so that's always a good place to start. Bonus feature is a 1988 F150 ECM that also failed. Not every unit is an easy repair, but there's a good chance some simple repairs can get you back on the road.