2015 2500HD 6.0 seems down on power

fjtort2 · April 29, 2017

My truck seems to be shifting more and seems confused more than ever. Especially around corners or when you let off the gas then hit the gas again. I think its more of a transmission tuning issue. 35,100 miles. Recently changed the oil. Truck has been great. Seems like the shifting issue is getting worse. Almost like its back in "learn" mode when I picked it up from dealer. Maybe I had some bad gas?

Any tips? Thanks

Doug Rosewood · April 29, 2017

Has the outdoor temp changed where you live? My truck behaves a little different comparing cold temps to warm temps..just an idea

fjtort2 · April 29, 2017

The weather has been back and forth.. Iowa weather.. Mid 30s mornings to 75 afternoon temps. Back to 40s for highs.. Crazy

Doug Rosewood · April 30, 2017

I'm no mechanic, but I think the outdoor temps will effect timing and fuel trims.hopefully a real tech will chime in for ya

HeliMark · April 30, 2017

Bad gas could always cause the engine to run screwy. Put some known good stuff in and see. Really what you need to do at this point is go back to the dealer, or someone who has an OBD reader that can get into the hidden stuff. If your engine is doing something or your tranny, it should show there. Maybe have the dealer reset the tranny.

As far as temperature, although you may get a very slight difference, the ECU with all the temp sensors should adjust all the inner working stuff to get the engine to run correctly. If you have a bad sensor, of course again, screwy stuff that should show on the OBD.

If the truck was running fine prior to the dealer changing the oil, I would go back to that point and find out what was done to the truck. Something changed at that point.

Mark