This is the third time I have thrown the following set of ODB II codes:
P0301 - Cylinder misfire cylinder 1
P0303 - Cylinder misfire cylinder 3
p2620 - Throttle position output (I haven't really seen a clear description of the code only a generic ODB description)
All three codes are on a 2011 wrx with approx 54K miles on the car. I have had it back in the dealer twice both times the tech came back saying that they couldnt determine the problem and reset the CEL, noticed a ~2-3 roughness on both cylinders but not consistent at idle.
I have run through the following:
Changed plug and gapped to .28 (NGK)
Ran MCCC to remove carbon deposits from cylinder heads
ran fuel injector cleaner through
swapped coil packs 2-4 to 1-3 when changing plugs and returned to 1-3 (didnt follow coil packs)
checked coil pack connections, not lose or stripped/exposed wiring
No lightweight flywheel or modifications.
Inspection of houses for visible cracks or tears (none found but haven't completed a leak down)
I also blew the TB-intercooler hose (blew out one side of the donuts on the stock hose) and have replaced with an AVO hose, this is literally the only change from stock. I have noticed a lag in during shifting under load, possible turbo leak or at TB-Intercooler.
I have been dealing with the dealer, trying to be patient with a car that I absolutely do love and want to continue to drive, the car is still under the extended warranty, but after the last time taking it into the dealer, them hooking it up to the computers only to tell me what a 10 dollar scanner could tell me and proceed to charge me 118 dollars, I am definitely gun shy in brining it to back. Per the dealer, they could definitely determine the problem if I authorized a motor tear down, 1100 dollars of course, with no guarantee that it will be able to solve problem. Truthfully lost all faith in the service techs and subaru at this point to stand behind there product. Had the service manager tell me if i drove till it blew up they probably would have better chance of fixing under warranty, unless of course they determined it was my fault.
At this point I am turning here for some advice or recommendation, I have read the misfire code help page:
If you have misfire read
Completed all but leakdown/compression test (currently dont have the tools nor time to accomplish), has anyone heard of requiring a valve job with this low of miles?
All help appreciated