Anyone ever had this happen. I am helping a family with their 96 5sp sohc neon. Driving had hesitation and stubbled pulling a hill in 3rd and 5th gear. Started by replacing wires, spark plugs and air filter. Have a new fuel filterbut need to install it yet. While test driving, encountered a miss. SEL came on, both flashing and steady. Upon inspection found Cyl #4 is firing the plug but the injector is not operating. Switch injector with #3 and the miss stayed at #4. Pulled the codes P0204Injector Circuit #4 open, P0304 Cyl #4 misfire detected. Checked the wiring from the injector to the computer for continuity and resistance. Wiring checks out fine. Pulled fuel pump fuse to reset the computer and the SEL came back on and #4 still missing. Is it possible that the computer has turn #4 injector of intentionally. I have hashed this over with my fellow coworkers and we are all stumbed even being somewhat automotive literate. I have been reading the forums lately and have learned quite a bit. Need to replace the platinum spark plugs also. Can anybody help me. Adam

 

All the wiring checks out fine.. hmm the thing that comes to my mind is maybe a bad ground (unlikely, though possible) or something in the PCM is fried, in which case you need to replace it.. Did you check the connections on the plug for the injector? How do you know its not working? Did you seat the injector correctly when you swapped them? Make sure somewhere the wiring isn't pinched and grounded out.. As for the SEL flashing, thats definately something severe.. Thats why I am thinking the PCM needs replaced..

Hope this helps!

P.S DEFINATELY change out those platinums!

 

could it be the timing?

 

I would think that atleast the injector would be operating.. I suppose it could be though.. But wouldnt you feel it through all the gears?

 

pulling #4 injector connector does not affect the engine at all. Using a screwdriver as a listening device, i can hear the other injectors fireing but #4 is quite. Purchased NGK aprk plugs this evening, going to go put those in and see if there is any difference. Pulling at straws here. Trying anything reasonable.