Hi,I recently replaced a 3.0 in my truck,at first it ran fine except it wouldn't idle when hot,, in the process of troubleshooting that i swapped my injectors out, then it started but ran rough,figured out 3 of the injectors were not delivering fuel,so i pulled them out and replaced them with injectors from the old motor which ran fine(even at 340,000 miles i should have left it in),now when i try to start it ,it will fire ,rev up and die,,if i keep my foot on the gas and feather it it will run but as soon as i let off dies. Thoughts?


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I have jumpered fuel pump it runs but no change,swapped throttle bodies,no change

 

Are you 100% sure all the vacuum lines are connected properly?

 

To the best of my knowledge they are,went off diagrams from here.it was running,,˟˟˟˟ty but running now all the sudden this,i dont get what could have triggered it

 

I don't think it should die even if some cylinders aren't firing due to faulty injectors You can try to take off one coil per time and see if anything changes.

In any cases , I would start from rechecking the vacuum lines. Even two swapped can make it run like crap. I spent hrs looking for issues just to find out had reconnected something wrong. Many times....

 

I follow ya,,I deleted the egr and pair so the lines left are fairly easy to hookup,,but Ive been known to cross em up,,I'll recheck

 

I had a similar issue when I deleted my EGR. Did you replace the single bolt on the front left of the intake manifold? I don't remember what it holds, but it's easy to forget to put back. Replacing this solved all of my extremely rough idling issues. Good luck!

 

I figured it out,,the plenum gasket was torn in the back and i didnt notice it so big leak there,,but thank you guys for your input.