Ok so I'm hopeing someone has an idea. I have a 98 dakota with a 5.2 out of a 99 1500, it had a 3.9 from factory. I've been trolling the threads for help. I purched the truck as is. The engine is missing and i have a loud popping noise coming from the exhaust. It will idle ok for about 5 min then it starts missing and dies. it also dies when stopping. I had a couple codes, p0138 (#2 o2), P0351(coil), P0320(crank sensor), P1391(cmp ckp).

I changed the o2 (did not use bosch), changed the crank sensor and mag pick up, plugs, wires(triple checked order), cap, rotor,cooling temp switch. the coil code comes is from switching to a msd ignition system. Its burning a large amount of fuel, 1/4 tank in 8 miles. still missing after about idleing for 5 min. on take off it chugs and back fires till about 40mph. (sound aout like a harley) then smooths out quite abit, but still misses. The tach bounces as much as 1000rpm when its chugging.... If anyone has any other ideas, it would be much appreciated.

 

check the coil that usually is a sure sign of coil failure runs for a few mins then starts to go crappy as the coil heats up. also check to see if your getting the proper signal from the PCM I have seen Dakota's that the PCM will fail like this and screw up the signal to the coil or not send it at all

 

Ok, sorry ive not been on in a bit...changed the coil, no differnce, disconected the MSD ignition, re hooked up the factory ignition. no change. how do i check the pcm? Also its not actualy a back fire, its more of an exhaust detonation. i was told that the distributor might be a tooth or so off, would that couse this?

 

Well, checked the positioning of the distributer made an adjustment(it was half way between 1 &8 on top dead center)ran a little better untill it wormed up then same missing and exhaust detonation... only codes are still for Po351 and p1391. any other help?

 

If you adjusted the distributor did you reset the fuel sync?