Guys,

I have an 03 Silverado 4x4 with the 4.8L and 3.73's. I also have 285/75/16 tires on the truck. I bought an SPE Proflash and played around with the tuning for a week or so and started having problems at WOT with the RPM's spiking at 6k and not shifting unless I took my foot off the gas. I was advised to put the stock tuning back in and start over. I put the stock tune back in but now at WOT with the stock tuning back in I am still having the rpm's spike to 6k when I floor it and it stays there until I let off the gas and get back on it again - then it shifts. I can understand it doing this with tuning in and making a few tweaks (tire size, shift enhance, etc) but with the stock tuning it shouldn't still be doing that. I don't see how any of the tune could be left in and maybe there is a problem with the trans? I did run it in High perf mode for a couple days with ***** to the wall driving and it seemed like when I changed the tune to a more modest setting for driving it on the highway 50 to work that I started having the WOT issue. Any thoughts or help?

SPE recommended putting a tune in with the stock shift enhance and stock shift firmness and if it is still having the same issue to take it to the dealer and have them check it because something could be wrong in the trans. Any advice or experiences? Thanks in advance!

 

I tried an SPE Proflash before with similar results. I hated the way it shifted. It caused me to hit the rev limiter twice (first time was real scary until I realized what happened). I have also heard stories of handheld tuners not uninstalling properly - and leaving problems behind in the PCM.

I returned the proflash and got LS1Edit. Now I know exactly what is being changed in the PCM calibration.