i am having trouble with my 3.9L. It cranks and starts fine but when i run the rpms up 2200 the engine starts miss firing and and stalls. at first i thought it was and ignition problem so i checked cap and rotor which was worn but not damaged but i replaced anyway being as they are cheap parts. next i checked the spark plug wires with my ohm meter and they passed the spec alldata gave me. next i started checking sensor inputs with a lab scope and the only thing i could find was a little bit of "trash" or interference on my distributor position sensor output to my pcm. so i replaced it and still no luck. i also have double checked my firing order and it is correct. next im thinking i should replace the ignition coil as im starting to run out of options and ideas. does anyone have any ideas on what could be causing this????

 

The distributer could have moved. Put #1 cly TDC and make sure the rotor is pointing directly to #1 on the cap.

 

just checked and when i put cylinder #1 to TDC of intake stroke the rotor was pointing directely to number #1 on the cap. so thats not it...

 

check your fuel pressure, make sure it's not dropping down. The spec should be 39 psi +/- 5 psi.