2016 Race Red ST3, 2867r gen 2, 4 port aux, 380/380 at 26psi 93 oct
Hey guys, been chasing this issue for about 4 months now, the dealer couldn’t find anything. Car is a 2016 focus ST. Mods are full bolt on, 2867r, 4 port aux, and dyno tune. The main symptom is bad almost stalling idle, when taking off from a stop the car stumbles and hesitates in first and second gear below 4K rpm, and randomly I’ll get “hill start assist not available” even when hill start assist is turned off. Current list of things I’ve done, replaced every sensor on the engine, replace direct injectors, new plugs, new coils, did every splice on the harness, new purge valve. The main code it throws is p0172. Once the stumbling stops the car still runs like crap, any little touch of the throttle instantly sends the car into boost, also the vacuum at idle sits between 0-1. Ive done a compression test and all 4 cylinders came back with 1-2psi difference. Even a tuner hasn’t been able to find anything on the logs. So I’m turning to you guys! I am trying to post a data log as well! Thanks guys and gals!