Everyone likes a good mystery to solve right? Picked up a nice 2009 Outback 2.5i with 95k miles for a great price. Drives smooth, in great shape, the only problem, it throws a CEL for cylinder 1 and 2 misfire, but only at WOT near redline. It's also a pending fault, so the CEL doesn't stay current once out of WOT. The rest of the time it drives normal and smooth. Luckily I don't take the NA to redline much.
Incidental findings: The TPS sensor reads 14% at pedal up, and only 78% at WOT. It's the drive by wire throttle body and not adjustable that I know of.
Talking to the previous owner and looking at the Carfax, things seem to start to piece together.
7/2008 - 12/2011 - Only normal stuff reported, oil changes, title, etc
12/21/2011 - 26,000 miles - Minor accident to driver side fender
1/21/2012 - 26,248 miles - Fails emissions (pretty low mileage to fail emissions, a rational person could reason the CEL problem started here with the accident, although in Colorado you can fail emissions pretty easily for dumb stuff)
1/25/2012 - Passes emissions
2/29/2012 - Car sold to owner #2
6/2/2015 - 52,448 miles - Fuel injection system flushed at Grease Monkey
6/9/2015 - 52,630 miles - Induction system service at Subaru dealer (seems odd to do two fuel system services within a week, but then no more records for 4.5 years)
2/17/2020 - 82,952 miles - Car sold to owner #3, who purchases extended warranty
3/20/2020 - 83,467 miles - Engine is replaced for cylinder misfire, does not fix the issue (not listed in the Carfax, found this out by calling around). Also don't know if this was a shortblock with the rest swapped, or a full long block.
1/17/2021 - 95,000 miles - Owner CarMax's car with "major engine issues"
It seems this has been fuel system cleaner'ed to death, plus they replaced the engine with no change (crazy!). So what's left?
1) Voltage? Reading 13.8 with the car running, haven't looked at WOT.
2) Bad grounds? - I've pulled each and cleaned them, I'm going to replace the bottom two.
3) Fuel pressure? - haven't checked
4) Coil? - Have a spare I'll try, but it looks like someone may have put a new one on from how shiny the brass standoffs are. I can always check resistance on it. Has new plug wires and plugs.
5) MAF - I did pull it and clean it.
6) Damage to the bundle of wires in the driver's side fender during the accident? - I would think I'd see it more than just at WOT, but this seems plausible?
I guess I could also hook it up to a datalogger and log a pull when the CEL happens. I'll have to see if the cable for my '05 LGT works for this car too with the CANbus. What am I missing?