Brother in law's 96 dodge 1500 w/ 5.2L keeps having problems. Just replaced oxygen sensor 2 years ago, transmission 1 year ago, crankshaft sensor and radiator 1 month ago. Now the problem is when pushing gas pedal, the engine revs up and down rapidly. No when sitting in park idling, but when going and if you rev the engine in park. Any help would be great!!

 

Test or replace the throttle position sensor. Disconnect the negative battery cable when doing so. Also check for any stored codes. http://dodgeram.info/Engine-Gas/OBDI/pcm_fault_code.htm

 

you taking about just checking the TPS with in the codes? the code came back as 12. i didnt disconnect negative when doing though

 

No, physically test the TPS. You can check the signal voltage, or, just measure resistance of the sensor itself, as you run it thru its range.

 

Since you have a 96, get a haynes manual and an inexpensive analog mutlimeter. With those 2 things you can check most if not all the sensors. Plus there is lot of other info in it you might find valuable. Disconnect neg bat cable when replacing or cleaning any sensors or doing any replacement of any electrical component.