I just got the APR tune for my 07 2.0t 34k mileage...running the 93 program with a forge dv installed to handle the added boost...the car ran fantastic huge power increase and better gas mileage after the install and i was very happy...Then all of the sudden the car starts studdering around 3k rpms feels like a kick from the rear(surges forward) at 1/4 to 3/4 throttle... at full throttle it doesn't feel as fast(no surge though)...the only thing that changed was i filled up at hess 93 octane that day and trouble started the next day...Called APR and Forge and they both said the symptoms are pointing towards a bad batch of gas...i set the car back to stock and it runs fine no problems...to trouble shoot i am going to run the car down to a 1/4 to an 1/8 of a tank put in 100 ocatane cam 2 gas and put the tune back in at 93...wondering if anyone has experience this before or has any idea what is happening...installing a boost gauge asap to help check on this as well...PLEASE HELP

 

Honestly, I've had issues with Hess gas in the past.

I had a supercharged 350z that was perfect until I detonated in one cylinder one day. The only change I had made was that I put in Hess 93 octane instead of my usual Mobil/Shell/Sonoco.

 

I've heard bad things about Hess. I've never personally experienced it, but I've heard that they have been known to inaccurately represent the octane level of some of their fuels.

Hope that's all your problem was, please let us know if better gas fixes it.