Hi, i first thank you for taking the time to read this. i just bought a 6.0 powerstroke f350 about a week and a half ago. I noticed that the truck drives fine when not bringing it over 2000 rpms. but it does have a four inch straight pipe i decided to open up a few times so far when it was warmed up. i noticed when it got to about 3000 rpms going from 2nd to 3rd it doesnt want to shift. i have to literally let off to let it up shift other wise it just lags there and holds the same rpm. curious if anyone has had the same problem and hoping its a stupid one. other then the pipe truck is stock was a plow truck which worries me

 

That's an engine problem. If it were a trans problem the RPMs would change. Find out why it's not making power at 3000 RPM.