i have a 99 dakota with 3.9 and it would randomly run rough and rich . when it was running rough i could unplug the first four injectors and it would run the same so i figured the injectors were sticking and replaced all 6.it ran great the 11 miles to work and i would say about 3 cylinders on the way home ..it threw no codes but was smooking and you could smell raw fuel so i checked the injectors and 3 are fryed .i figured because they were chepos from ebay that was that so bought 6 new from dealer and it ran good for 10 minits and back to rough running again and is now giving code p1203 so i check with a noid and i have pulse and power and if i unplug injector i can here the idle change ..the only thing i can think of is the pcm is dying...does any one have any thoughts thanks

 

How is your fuel pressure? Might also try unplugging the front O2 sensor(s?), see if it runs any better.

 

fuel pessure is 50 psi when its running good then when starts running like crap it rapidly moves between 40 and 50psi id swear the pcm decides in order is to much work and starts firring all injectors at once.....i tryed it with 02 unplugged and still idled rough but if tryed holding rpms up any over 1500 was back firing rapidly ...Things i have done i pulled and inspected engine harness and recovered with new loom, new mopar crank ,snd cam,sensor,,new map,tps, and air temp sensor and 2 sets of injectors 1 chep set and the new set were new bosch.... the injectors it killed went from with inspec ohm reading to zero continuity....i ordered new plugs to replaece the fuel fowled ones that are in it now only 300 miles on them,and new 02 sensors ..having little trouble finding a pcmas the number on mine dosent match any i find (i probably rote it down wrong) thanks for any help

 

What plugs did you put in it?

 

there champions for the last 300 miles had e3's for the last 3 years only swapped them out because it would show cylinder #2 miss fire code randomly for last 3 years

 

Did you clean up throttle body ?
02 sensors can factor it too.Check 02 readings an short term an long term fuel trim reading.
OEM on all sensors .

 

yes was cleaned when did intake mods roughly 2 months ago and still looks clean as well as in side intake ..i also cleaned all factory grounds and all the others i have added ..i need to pull injectors again to see if one is stuck as i noticed that it has pressure when running but drops almost instantly to 0 when shut off

 

yes i did put a noid on it. used my home made light and also a rental from parts store and i got pulse on all injectors.

 

Did you change the distributor cap, wires and/or coil? A weak coil can cause higher RPM issues, a cracked/tracked dist cap can cause misfires, and failing plug wires can cause all sorts of weird crap. In any case, changing these parts is a regular maintenance thing anyway.

 

yes i changed cap rotor and wires evan put on wire seperaters.but i did nor replace coil and its an accel witch i have herd are not veary good but was on truck when i bought it ..would like to get something other than stock but been to lazy to see if any thing is made that works better than stock for a coil