Columbia long start, loss of power and decreased fuel economy.

I have an automatic 06 Columbia with a MBE4000 engine that I parked at the end of my day. All was fine that day. Truck ran great. The next morning it took forever cranking to start and idled rough. While driving I noticed a loss of power and fuel mileage. Loaded made it even worse. Had to keep the rpms on the high side of each gear as long as possible just so it would not bog down so quickly when shifting. Shop said I had #2 fuel injector pump that quit so I had them replace it. No change. Then they said #1 injector pump was showing at 50% so they replaced that. No change. 2nd shop said it could be injectors but would have to replace them since there is no way to test them. 3rd shop said its not mechanical but the ECM has a corrupt file and is causing all the problems. Suggested replacing it with a used ECM to fix the issues. Any advice would be appreciated.

 

Engine version?

 

Not sure about the contribution test. I haven't been told what test/tests were done. The only code is the egr code and a check engine light from that code. Wondered if the egr could be causing this but no one can give me a definitive answer. Wanted to delete the egr.

 

That would make perfect sense since these symptoms happened suddenly. So i got the sensor from the dealer (now $40) but is this a DIY repair or does a shop need to do this?

 

I actually took it to a shop to have the egr deleted to see if that would make a difference but mechanic back tracked after I left and started diagnosing other issues and when I questioned him he tried to say the egr wouldn't cause misfiring so I took my truck back.

 

Replaced both crankshaft and camshaft position sensors with no change...ugh