Miss at high boost - 3 CEL Codes

[tweek814]

Hey first off here are the codes i read with an obdII scan tool -

P1400 Manifold Differential Pressure Sensor Circuit Malfunction
PO505 Idle air/control Motor Malfunction
P1105 Fuel Pressure Solenoid Malfunction (turbo)4g63t

Cleared the codes yesterday and they came right back overnight.

Anytime I go over 10 psi, give or take, wot, theres a heavy miss. I turned boost down from 16 to about 13 and it seems to have helped to an extent. Most noticible when your wot in 4th or 5th gear at low rpms/full boost. Gonna do plugs, wires, replace iac (idle surge once and a while) and go back to stock o2 manifold. (has o2 dump atm) would do the fuel filter but i learned my lesson last time, ill save that for another day.

car is 96 tsi awd, boost controller, o2 dump, 3" o2 back exhaust, air filter, boost a/f gauges, 5 speed.

thanks in advance gurus!

 

[khartley]

Well, the 1st may have something to do with a vacuum hose being disconnected or something stupid like that. The 2nd is self explanatory. The 3rd may have something to do with your missing, cause that sounds to me like fuel cut, and I would definitely try and stop doing what your doing if you like your engine and don't want an excuse to melt a piston.

Just out of curiousity, what is your boost controller set to? If its much higher than stock, you definitely need some fuel upgrades.

 

[tweek814]

Boost controler is the whole way turned down still hitting 14 psi and then I just noticed a bit of boost creep in higher gears

Its not missing or cutting out anymore but still all 3 codes keep coming back. Haven't replaced iac yet or blt