I would consider the tranny solenoids or tq converter slipping. Niether will light up the engine light but if scanned will throw a code p0740

That really sounded like the OP issue. But as for your new issue, I woudl assume a tranny shop would have scanned it so that is going to rule that out

 

Yeah, they did a scan when driving it and didn't find any codes being thrown. They indicated the tranny is working correctly and it's a good shop so I believe them. Glad it's been ruled out, but sure wish I knew what it was.

Would a bad injector cause this? From the shops write-up during driving and monitoring the ECU data, "found no data very far out of range, fuel trims bouncing somewhat." It's odd it's only in a certain RPM or speed range. It seems to be the worst around 65 mph, which is about 1800 RPM. Speed up to 70-75 and it smooths out.

I found in the service manual how to test an injector and I'll probably go through and do that (fun), is there a way to test if a coil is bad?

Truck has 64k miles on it.

Thanks!

 

You would think a bad injector would throw a 300 misfire code.