2004 ford taurus 3.0 ohv p0351 hesitation under load and idling comes and goes

Hello I have p0351 primary/secondary coil malfunction code let me give you some background on issue. It started one day i pegged the throttle and it just fell on its face going up hill then was ok. Of Course it came back so i started by pulling off coil wires i have block coil and found #5 dead but no codes at that point wierd but replaced coil and plugs and got better but still had hesitation when throttle is snapped and under load heals lite coil/injector shutting down. so i started monitoring data list and saw the mass air flow reading voltage while engine off key on so replaced it and now says 0 when key on engine off but problem still there had got a cam sensor code at that point and replace sensor. recheck but problem still there checked and pcm is getting crank signal replaced crank sensor for shits and giggles was cracking but didn't think was going to fix it. So at this point i swapped injector 1 with a front one that was easy to replace if it was bad. under skipping condition while listening to injector it would tern off but later realized the pcm was shutting injector off to protect cat i think anyway cuz i got same p0351 code after injector swap. Now i checked the power at coil pack and its getting its 12 volts and then i checked the ground pulse side with test light its all i have at the moment also have multimeter at work anyway i have a 4 pin coil connector pins 1234 pin 4 has 12 volts engine running but pin2 is pulsing really bright compared to pins 1 and 3 and when i apply the test light to pin 2 the engine seems to skip compared to pins 1 and 3. i inspected wire harness and do not see any rodent damage or corrosion. im thinking the coil driver in pcm is shorted mabe what do you ladies and gents think. Thanks any input would help

Hey hondaguy! To be clear, this is NOT a dead misfire as of right now, correct? As in, it's not misfiring all the time, just intermittently?

For clarity, I grabbed the wiring diagram:





For the P0351 code, it's pin 1 that we're really worried about. If the pulsing from pin 1 really is significantly weaker than pin 2, then you may be on the right track with a PCM problem. I think the next step would be to repeat the same test at the PCM itself, to rule out a possible wiring issue.

While you're testing, have you tried giving the coil connector a wiggle while the engine is running? Just a quick test for connector issues, and might explain intermittent misfiring.

hello thanks for the reply. its yes and no i started it up this morn it started up seemed to run ok for minute and then like a switch terns off starts to skip. i checked throws diagrams and have the power going in to coil on red wire but cant remember what pin it was think was pin2 was noticeably brighter than other 2 coil pins and test light was flickering as driver switched on and off now from what i understand the coil driver in pcm fires both cylinders at once so maybe its not firing the coil driver correctly not sure this one got me good. i work on cars for a living and have had lots of electrical diag problems before but cant figure it out wires look good. i got pcm for cheap so gonna swap just so weird mabe coil driver shorted in pcm

New computer will need to be programmed. Your better off doing a little diagnosis before you start flinging parts at it.