Ok i have an 87 turbo 5spd, i have a full 2.5in exaust(No Cats), the K&N FIPK, and an autometer Vac/Boost gauge. The car just started doing it today(Mid 40s outside) when i shifted into 2nd from 3rd, i got to second under 2500RPM and nailed to pass a car and as soon as it hit atmospheric pressure it fell on its face from 0 to 5.5-6psi then it pulled hard all the way too 10psi. Now it stumbles when you feather it at idle, backfires like a 12gauge, and sometimes stalls. im thinking the CSI, but i also took of my factory afm and am using one from another supra turbo. So before i throw the ol' DMM at this bitch, SOMEONE GIVE ME SOME OPINIONS!
STUMBLING PROBLEMS PLEASE HELP!!!!!
- Thread starter TheNewRed
- Start date
I'm having a similar problem and I still havnt figured it out. Mines not throwing any codes at all.
MAF. also venting the BOV to atmosphere will do it as well ( the higher the elevation it seems it is more likely it will do it, makes sense to me 
in texas it wouldnt stumble at all and in colorado it would stumble every time i boosted until i recirculated it and it never did it again )
reset the ecu and see if it still does it
in texas it wouldnt stumble at all and in colorado it would stumble every time i boosted until i recirculated it and it never did it again )reset the ecu and see if it still does it
mine i think ended up being my fuel pressure regulator. I was stickin ether wide open so it would run lean or all the way shut so it would run way rich. Just kinda depended on the day.