My 99 Dodge Ram 1500 5.2 is misfiring running at low RPM's and when going up hills. I have replaced the plugs, cap, rotor, and wires. The motor seems to run fine under idle. Any idea's? I have been told maybe a crank sensor.

 

Have you looked at your plenum yet? Checked fuel pressure?

 

what is YOUR definition of a misfire?

 

I have the same problem around 40-50 and my 5 and 8 plug look like they are the ones misfiring. I thought it was the routing of the wires but it did not solve the problem. Will a blown plenum do this???

My 5 and 8 plugs do have oil on them or burnt oil. Maybe I will do the vaccuum test this week to see. If some one comes up with a better idea please let me know.

 

Plenum gasket, precat o2 and cat is shot/clogged or almost there.

 

I will take some runs with the pre cat O2 out and see if it helps. Thanks for the advice.