Kevin Kruft
Junior Member
We have a 1999 Dodge 2500 5.9L Gasser with rough running issues when it is hot. I am, well I thought I was a master mechanic with my own shop. When this truck gets hot it runs terrible. Sounds like it has a cam in it. RPMs are all over the board 500-1200. We have replaced the crank and cam sensors, distributor, cap, rotor, plugs, wires, tried a replacement ECM, checked the o2 sensors, IAC, checked all the wiring, checked the TPS and MAP sensors, coolant temp. When it starts to die and picks itself back up you can see it lose spark for a second with a spark tester and then it comes back. We have replaced the coil twice. Truck throws a p0351 and p1391 codes. When it runs rough the converter starts to get extremely hot but I ran a test and drilled a relief hole in the y pipe to no avail. Doesnt appear to be a plugged converter. The loss of spark when it goes to die is what baffles me. Plenum pan is clean and doesnt appear to be leaking vacuum. I am at a total loss. Please help.
Thank you!
Thank you!
