I have a 07-2500. 5.9 with 56,000 miles. recently when i start it up first thing in the morning, it starts up but idles ruff like a misfire for about 3mins, and then it runs and idle fine after that. Fuel filter has been replaced and i donot have any check engine light or codes on. Any ideas ? Thanks for any help.

 

Hey, did you ever find out what was causing this issue?

 

+= Bad injector!

 

I'm starting to lean towards bad injector but how do I find which one. Ive done a return flow test which passed... was going to ohm them out today. Any other tests for injectors?

 

A friend of mine who has worked on big diesels for years said they would use an ir thermometer to monitor each exhaust port temp at the manifold after startup with throttle held above idle and watch for one port/manifold to stay cold longer than the rest. Or from startup above idle they would use a tire paint marker and mark each manifold port area and see which paint mark stayed longest as the others melted. Good luck.

 

On a 3rd gen you can remove the valve cover and remove a wire from the injectors one at a time and whichever gets rid of misfire or engine reacts the least is where to start.