Heatsoak? Low mileage and power extreme power loss.

[awsomeeye]

I got my FiST less than a week ago and a few days ago i noticed the car drops power noticeably when driving around town. I drive economically 99% of the time and do maybe one 2nd gear pull per drive which is short. My driving is primarily city driving but even without traffic in 80-90 degree heat im getting this issue almost immediately after driving for only like 10 minutes. Also my average gas mileage is 24mpg... this seems insanely low. whenever I drive at night in 60-70 degree temps as long as the car hasnt been driven constantly throughout the day the power seems totally normal. Anyone have this issue or know what I should check? I unfortunately dont have an ap yet.

 

[SteveS]

Is your car modified? A stock FiST should be able to handle a lot more than that without problem.

 

[gtx3076]

All cars lose some power in hotter weather. I would recommend buying an accessport so you can perform a log to see what, if anything, is happening.

 

[NATYPE]

Driving around town I recognize it's incredibly easy to be just throwing away gas in this car. When I was stock and especially now that I'm tuned. Seems like a moment of quick mindfulness is all it takes to pull my foot back that tiniest bit and suddenly see MPG's in the 30's. If it just let whatever residual muscle memory I have from my last car control things I'm always in the teens seemingly.

Feels like the sweet spot isn't in an intuitive place for me. Not sure how much of that is just the stock turbo power band + fueling etc. I'll regularly be in 4th just a little too low giving it a bit too much gas when sitting at a higher RPM in 3rd nets me much better gas mileage. Just funny.

 

[awsomeeye]

Is your car modified? A stock FiST should be able to handle a lot more than that without problem.

all it has is a mountune cai. i agree though so i think something must be wrong.

 

[D-resonant]

Does the car have an upgraded FMIC?

The locked mountune MP215 tune and the later mountune (Randy’s) AP tunes all need a mountune, or larger, FMIC. You can easily heatsoak the small factory FMIC in 85F temps. You can identify a factory FMIC by its plastic end-tanks.

 

[Blk16 FiST]

Could need upgraded radiator. Mine would do sort of similar before upgrading the radiator, especially with A/C on

 

[dhminer]

Are you running premium fuel only? When was the last time you cleaned or replaced the air filter?

 

[awsomeeye]

Are you running premium fuel only? When was the last time you cleaned or replaced the air filter?

93 only! no exceptions. i took it to my mechanic that i trust and everything is a-ok. i was overthinking and i guess i got used to the power somewhat.

 

[DEss]

93 only! no exceptions. i took it to my mechanic that i trust and everything is a-ok. i was overthinking and i guess i got used to the power somewhat.

Still doesn't seem right. If you really drive economically 99% of the time you should be getting much more than 24.

DS