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Old 12-02-2020, 02:35 PM   #1
Scooby Newbie
Member#: 520674
Join Date: Dec 2020
Chapter/Region: SCIC
Location: CA
2008 WRX STI Hatch
Hyper Blue

Default 2008 STI Hatch: What could be the culprit?

P0102- Mass Air Flow (MAF) circuit is low, and that it is not performing within its specified operating range.

P0113-Intake Air Temperature (IAT) Sensor, specifically that there is a High Input Problem with it

PO123-Throttle Position Sensor Circuit High Input

P0223-Throttle Position Sensor B Circuit Input High

P2433-Secondary Air Injection System

Okay so here's the story, 3 days ago I was driving, doing some pulls and some spirited driving (nothing out of the ordinary) and nothing was wrong, no power loss, no overheating or weird noises, no CEL, nothing. I get to my destination and when I got back to my car around 30 mins later, it wouldn't start. Rough idling and sputtering, thought it was the MAF, so I cleaned it and put it back in to no avail.

I then ordered a new one and when I put the new one in, the same thing is persisting. The strange part is that when i unplug the MAF sensor, the car starts and idles pretty much normally. I have very spotty, if any throttle response, and it sounds like the engine is backfiring in the FMIC piping. I checked the coolant reservoir and overflow and it looked like there might of been a very very thin film of oil on top of the coolant but no cream sludge on the oil dipstick or fill cap. I double and triple checked all of the hoses, lines, couplers, and connectors and couldn't find anything that looked popped off or unplugged. After the car broke down, it heated up very fast while sputtering and the coolant overflow filed 3/4. There was also a decent amount of white smoke coming from the exhaust but the car is catless and fully built.

The strangest parts are that when I unplug the MAF sensor, the car starts and idles pretty much normally. And that when the MAF is disconnected I still get a reading for MAF on my Cobb AP, but when it is plugged in the MAF reading stays solid at 14.70. SO weird.

Considering the white smoke, the small champagne bubbles forming in the coolant overflow, the overheating and sputtering, and the sweet smell of burning coolant, is likely that I blew a headgasket?

Or is it possible that the combination of all 5 CEL's all relating to the TPS/ECT/MAP connections is to blame?

Last edited by 600hpSTI; 12-02-2020 at 02:41 PM.
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