Hi, I m new to forum chat but I m after some info/help

My 09 sti has a ppp fitted which felt very good, but after having a flat battery I ve lost the performance and its a nightmare on fuel, anyone else heard or had this problem, and can anything be done to retreave power, thanks paul 

Hi n welcome, Paul .

Can't say it's a common symptom but maybe if it had been remapped at some point ? It might have gone back to a different map , as some software allows duel maps .

Could be another fault ,misfire ,boost leak ,collapsed cat ect .

Any dash lights staying on ?

Maybe a ECU code read might help pin point any issues 

Hi, thanks for the reply, I bought the car already done, it does have the prodrive sticker on drivers door, and a rolling road graph with car. How do I go about a code read, any suggestions on where? I'm based in Herefordshire. Thanks

You have a OBD port underneath the steering wheel near your knees. Plug in an OBD reader and get any codes (pending codes).

I bought a cheap Bluetooth one and it works. Handheld ones work too.

https://www.amazon.co.uk/OBD-II-Engine-System-Diagnostic-Tools/b?ie=UTF8&node=2486228031