This is TheGrinch - It's because of front/rear speed sensors being off or something like that. More than one thing measuring speed.

This has been asked about 50 times and there's never a solution. I had a custom tune and it still did it before I bought HP tuners (although if lew can change VSS he ...

I tried putting in 33", nope, 295/65/18 so both the 65 and rim size were the same as stock, nope. $600 tuner can't change tire size without lighting up the dash lol.

Lots of people have the same problem with trucks that aren't lifted.

Just have to get in touch with Lew, $30 to delete rear O2's (or other sensors). Screen name Monte06SS.
http://www.diablewtune.com/

Please let us know if it's going to be possible to change tire size without error lights.

I'm going to try changing the aspect ratio back to 65, AND set the speed limiter 1 to 120 mph, see if that works. Will use a tire that's the same height as actual. They said something on some old threads about ...

So it's probably kinda like the ECO mode on a chevy equinox that bumps you up to over 30 mpg, vs the 24 mpg you normally get (but loses power). I'll have to play around with this.

Hey dude!! Check your PM's, figured it out, it actually reads the rear O2 sensors and calculates that into the LTFT and STFT's. Please send me tune with cats deleted so I can finally drive this thing!! lol.

Never have read that anywhere, always read that rear O2's are only for diagnosing the ...

Because I've been fighting this lean bank 1 problem when on CNG, and I hooked up the ecu to read only the bank 2 O2 sensor for both banks, so it's the same, and it STILL reads lean.

So, what is it, fuel flow rate sensor, what is on a 2008 silverado LT 5.3L non flex fuel? I really need help on this ...

lol ok, not sure why not though, it works just like petrol when it's working right, and you have to tune for petrol anyway because it's bi-fuel. The CNG has it's own fuel maps on a different computer. It just follows the car ECU's strategies for closed loop, enrichment, etc, and you fine tune things ...

Thanks, will be in touch.

I am curious how trinity calculates the LTFT's? Is it the same as the car's ECU? I get weird results when running on CNG, but everything works perfect on petrol. It will show +30 LTFT's. The car does act funny too sometimes, but giving it more gas just makes it run rough and will die eventually. It ...