Topic: 2006 WRX rough idle/hesitation/no boost

[bru_12]

Apologies in advance for the length.

A couple of weeks ago I had to run a quick errand (10 min round trip).  Halfway through the trip home I had to go up a hill and noticed the car wouldn't go into boost.  It felt like it was lurching, or hesitating right around 3k rpm.  I was away for the holidays and wasn't able to screw around with the car until this weekend.  I was able to start it and drive it around the block today.  The car idled roughly and had a hesitation/lurching at low rpm and at boost.  I monitored boost with my AP and noticed it would only hit about 6 psi in second gear.  The problem got worse as the day progressed.  Now after starting the car will run normally for about a minute, then drop to less than 1k rpm and idle very rough, then slowly stall.

Car is running the out of the box cobb stage 1 map.  I tried changing back to stock map but it didn't make a difference.  Car is mechanically stock besides the secondary air pump which I removed last summer.  Last work I did on the car was replacing the spark plugs, but that was in the summer and I've driven 4k km since then with no issues.

My biggest issue is that it's not throwing any codes.  I pulled the MAF sensor to take a look at it and it looks really clean - no obvious dirt or grime.  I had a MAF issue on an STI back in the day and it threw a code right away so I'm thinking that is not the problem.  I'm thinking it could be an O2 sensor or coil packs, but I would think that if those were the issue it would throw a code.

Any help would be greatly appreciated.  I'm hoping someone has an idea of where to look before I start having to throw money at this thing.

Thanks!

-Bru

[WRBSTI]

Little late on this, but my brother had the same issue when we pulled his motor, turns out he had a massive leak where the turbo inlet meets the turbo. That and we switched 2 vacuum lines up, but if you haven't done anything to the engine i would look for obvious holes and such in all your lines. Maybe check your turbo inlet as the stock one likes to fall apart

[Jay89]

Check for boost or vacuum leaks. Check boost lines. Common one to leak is turbo to Intercooler, or intake to turbo. Age cracks them and can cause some issues.

[StreetsTheWay]

My original OEM boost control solenoid on my '07 STI decided it didn't like actuating properly anymore and gave me similar problems. I tried cleaning it out and cleaning all connections incase anything was getting a bad signal and then tested it on the bench after, but it only seemed to make it a little better for about an hour. I just ended up getting a new OEM replacement and problem is 100% gone. Not sure if that is your problem, but it fixed mine!

[Ryhno]

Kinda had the same problem in my STi, found out it was my wiring harness...relpaced it and the car ran fine after that

[jer]

The other one to check, if it isn't resolved, is the fuel filter. Depending on mileage the 06's are getting to the age where it becomes clogged... Unfortunately that's in-tank and costly to direct-replace.

[Scooby Brew]

I am starting to see the beginnings of this same problem.

Already changed the spark plugs, gonna do the fuel pump and filter, and have leak test done.
Nothing to worry about, just the age and use factor. Should be an easy fix I think.