Any thoughts? like the title says I had the Intercooler TSB and PCM TSB done to my truck, seems down a little on power, not a ton though. But the MPG has dropped considerably. Before update I was getting about 16.5 doing 75% city 25% hwy way... same route to work every day. Its been two weeks now since the update and im at a 14.5 MPG and still dropping. I've ruled out bad gas, filled up 3 times (7-11 I know shame on me, shell and 76).

Oh by the way I had the TSB done because when I installed my tuner the truck would stumble on accel. around 3500rpm. Haven't had a chance to reinstall yet to see if it has been fixed.

 

Have you checked the gap on your spark plugs? They seem to be all over the place on the 11's. Most people are tightening the gaps down to .030 especially people running tunes. That could be why it was stumbling with a tune.

 

I had the dealership check the plugs, They said they pulled 2 of them and they where within spec... so no I have not and suspect it could be part of the problem, but that shouldn't cause a drop in MPG because plug gap has been consistent.

 

Did the tune improve your mileage when you put it in? If so maybe it's dropping since you removed the tune and not because of the TSB.

 

The tune did improve my mileage. Before the tune I would average about 16.5, after I installed the 5 star tune I was getting about 18, I uninstalled the tune to have the TSB's done and now I am getting 14.8. So its not just removing the tune that caused the drop.

 

Which 5 star tune were you running? I ask because most say that the tow/perf tunes lower their fuel economy. I seem to lose about 1mpg with the 87per/tow

 

the new flash strategy for the pcm tsb is probably richer than previous strategy....it also could still be relearning also....

 

I was actually running the 91 perf/tow and at first I saw a drop but that's because I couldn't keep my foot out of it, after I started driving more normal again I saw the MPG's climb back up. Never saw a drop though it always stayed about even.