Anyone ever noticed that right after ECU reset procedure the car drives like new, but then a few days later it's back to usual self, and in my case it seems to lose power. I cannot figure what's wrong with it. No "check engine" light. New MAF, new spark plugs, Amsoil motor oil, amsoil air filter, franken catback.
It is not like it's really broken or anything, but right after the ECU reset procedure i can light up my tires in second, and chirp in third, then a few days later i can spin wheels in first and only chirp in second gear. it just becomes less responsive.
How can i diagnose what's causing it? There are no trouble codes either stored or pending in the ECU.

 

Did you get the ECU update for the hesitation problem? If not, that's a good place to start.

 

If there are no codes sotred/pending, why is it on in the first place and why do reset it?

 

He didn't say the light was on. He is just resetting the ECU, so the car will "re-learn" optimum settings.

 

I really wouldn't say that anything is wrong with your car, but it sounds like when you reset your ecu the car is running lean, then after about 40 miles of mixed highway and city driving the ecu relearns the optimal air fuel mixture for fuel economy/ power. Hope this makes since.

 

Everyone,
Thanks for your replies.

I think that mrmj1218 might be right, i mean the car does not become gutless, i guess from the factory they're more concern about fuel economy and emissions and not the power, so after driving cycle ECU relearns and "optimizes" the mixture for those things even though it has to sacrify power output a little bit.

I wish the Technosquare ECU reflash was cheaper, then I would try that.

No, I did not.
How much would that cost? I'm out of warranty, so don't want to get ripped of by the dealer. Anyone know a good place to get it done around the Phily area?