Do you have a 6.2 with vvt? Tuning those has proven to be pretty damn tough, and Ive heard of mileage tradeoffs with them, but only the vvt motors. Seems like the tuners havent gotten them fully sorted out yet

 

all truck 6.2s have vvt so yes

 

I did my own tune. I have ordered headers, but I was sent the wrong ones (5.3). But, I have a few compare tunes that I am using to build my tune once they are installed. My mileage has gone up roughly .5-1mpg with the tune though.

 

I have a 5.3 that has been tuned. I get 20 MPG all day long. This is at 70mph
with the cruise on in hilly area. Just got my Kooks in this week and I'm not going to re-tune it, just turn off rear cats. We'll see what happens.

 

What year ....body style ... trans/ rear gear

 

All 6.2s have vvt, but that doesnt mean you are utilizing it. Alot of guys are deleting vvt and afm because of the tuning problems. I would try going back to the stock tune to see your results. Like I said, the vvt motors aren't showing the ideal results from a tune, like everyone was hoping for. I personally feel it is because the vvt has already optimized all the parameters regarding fuel and ignition, and that there is no more room for improvement on that end. This issue keeps popping up. Just my opinion, but what do I know

 

Tuner 1 modified VVT for low mid nothing at WOT, tuner 2 made mild VVT changes and at WOT

 

Sorry man, but i'll have to disagree with you about the VVT stuff. We have a tuner down here that has been pulling 30-40hp/tq under the curve, I'm talking from 2k-4k.

LloydTX has had his trucked tuned by Said person and im sure he'd be more than willing to vouch for his work.

 

Have you read Lloyds posts about it?

 

Indeed, I know his Quarter mile results were less than stellar, but there is so many factor in running a good Quarter mile time that i won't even get into that lol.