My problem all started when I was driving. Threw a P0208 while driving and than the engine died less than a 1/4 mile as I coasted into a parking lot. Ok no big deal, the injectors are the original on the truck (316,000, rebuilt 40k miles ago, 5.9L Magnum, 99 4x4) and figured they are due for replacement. Tested the resistance on them, all around 12.8 with another injector in the 12.3 range. Wiring going to the injectors all look good as well. Well I ordered a new set of Bosch p/n 53030778 and realized that these do not have the little notch for the clip to hold the injector in place. I decided to give it a go with them, started up the truck and now I got a P0202 code, same horrible idle that is super rough. Which is bizarre. I had my computer sent in to SIA electronics for diagnostics since it didn't make sense to jump codes to a new cylinder. This is where I am at now. The company had to re-solder some loose components and the idle problem is a little better, but still rough.

1. Did I order the wrong part number injectors and this is the source of all my problems?
2. Since I had my PCM sent in, do I need to have it reflashed by the dealership?
3. Is there something else I am missing? The truck is at idle right now around 900 rpm and rough as can be. Go to put it in drive and hit the gas, truck almost dies before gaining power. Thinking throttle position sensor?

 

1. The new injectors are not the source of your problems
2. No
3. It's not the throttle position sensor either and you're missing something.

Not to offend you but I don't understand the logic here. You did the perfectly right thing and measured the resistance of the injector coils. They all test good per FSM, resistance reading should be approximately 12 ohms +/- 1.2 ohms. And then you replace them anyways ... ?

The code setting criteria for P020X is if either the measured voltage drop or the measured resistance is too high or too low. Voltage drop is sort of a stand-in for resistance (Ohm's law) so they are basically the same thing. The injectors have constant power on one pin and the PCM grounds the other side of the injector coil to fire them. Two possibilities: Supply voltage to the injectors is low, or the PCM has a problem. Don't know SIA but they probably don't test it on an actual engine.

 

No offense taken one bit! Electrical is not exactly my strong point here. So by looking at the issue after doing some reading, injectors test good and now my PCM has been looked at. SIA is a company that I sent it in to get checked out aka was not on the vehicle. I'm seeing my next step is to take a NOID light to each individual injector and see if it is getting supplied voltage.

 

A NOID light is a pretty simple works/doesn't work indicator. We do know the fuel injectors are basically working because the engine is running somewhat and you already measured the resistance so a NOID light doesn't really add any new information. The injectors and the coil are getting power from the auto shutdown relay so check what voltage is present at the supply side (dark green/orange I think on that year). Could also be an issue with the ASD relay, check for contact corrosion and swap with the A/C relay. Lastly, check the grounds at the front of the engine.

The tricky part with electrical problems affecting the PCM is that the error messages can be misleading. While PCMs do fail it's actually not that common. There are plenty threads on here where replacing the PCM did not fix a problem.