Try a cylinder contribution test. If your scan tool can do an injector buzz test (which only checks the electrical side of the injectors - I assume you didn't get any injector codes or anything associated with the injector wiring,) it can also do a CCT. It's cheaper and easier than checking exhaust manifold temps. You can also get a glow plug adapter and do a cylinder leakdown test.
All that is cheaper than shotgunning parts at it.

 

Hello klhansen I have a laser temp gauge and the #1&2 cylinders are just over 100 degrees at the exhaust manifold. The other 3-8 are over 200 after a quick 1/4 mile drive. I appreciate the feed back. I can remember you on here helping out all the way back to 2003 when I got this truck

 

Also, you might try:

Check your wiring first, using and following this link:

Tech Bulletin 103

Then if the wiring checks out see if there is anyone near you that would have a spare IDM you could try and swap out.

I had an IDM with an intermittent short causing a miss and running on half a bank, along with several others on other forums I have messaged.

 

Thank You I will ask around for an IDM. I had this replaced about 10 years back. Owned the truck for 22 years

 

Do the Cylinder Contribution Test before you throw an IDM at it. A dead bank on the IDM would show up as a code on the Injector Buzz Test.

The more data you have, the better you're able to track down the actual problem.

A non-firing cylinder can be caused by lots of things. Low compression (rings or valves), Injector, Injector wiring, etc.

Exhaust manifold temps is a pretty rough test. A 1/4 mile run is really pretty short for that to give you good results. If you're going to do a manifold temp test, run it till it gets good and warm, then check. I'll bet you'll find them a LOT closer in temps.

 

Contribution test and then compression test. Rule out mechanical issues first.