I have a 2007 1500 Silverado LT2 with a 5.3 flex fuel/fuel management and I'm not getting a signal to the#1 coil to fire. Swapped coil and wire with #3 and no change. Put my timing light on the wire and get nothing. Anyone else ever have this problem? And it'* shifting like I have a shift kit in it. Hits hard in 2nd and 3rd.

Well, you either have a bad ECM or, you have an open circuit.....I would be thinking open circuit, possibly at connector X111....

Are you checking the wire just at the coil or are you going back to the harness connector, X111?

Basically, check continuity from the coil harness, terminal C, to terminal G at connector X111....if ok, then check continuity from G, to terminal 70 at connector X2 at the ECM.....if ok, need an ECM.....

Thanks for the info. Checked continuity and all is good all the way back to the ECM. Drove 50 miles one way to get the part the same day and took it to Raymond Chevrolet in Antioch, IL and they didn't upload my VIN or anything for that matter into it before they installed it. If I had to guess I'd say they didn't even disconnect the battery before they installed it. And charged me 1.4 hrs to install plus programming. I know this because I connected my super chips flashpac and it reads incorrect vehicle. But thanks again for your reply.