I've got this 2000 Subaru Legacy, manual transmission, with a 2.5L 4cyl. I've been getting occasional codes for bank 1 system too lean for a couple years now, but haven't had many issues with it and the car doesn't usually have any problems.
However, recently it started missing something fierce. I've only pulled cylinder 2 and cylinder 4 misfire codes off of it since it started running funny, and I've tried everything.
- Plugs, Wires, and Ignition Coil
- Platinum plugs and store band wires. Tried a replacement coil but didn't notice a change so I went back to the original.
- Vacuum hoses
- Replaced cracked vacuum hose going from intake manifold to fuel pressure regulator - that was probably causing my occasional lean condition on that side
- Also replaced vacuum hoses going to the EVAP Purge Solenoid (aka valve) under that side of the intake manifold
- not finding any vacuum leaks anywhere using the carburetor cleaner spray method
- Fuel pressure test
- Fuel pressure before fuel filter is well within range, both with and without the fuel pressure regulator plugged into vacuum.
- It's important to note that the fuel filter was replaced less than a year ago, and I've replaced it just about once a year for the past 3 years I've owned it.
- fuel injectors are ticking
- The o-rings were replaced on those about a year ago, too, fixing a pretty massive vacuum leak which I have double checked and is no longer there.
- Fuel system cleaner
- It's been running on 8 gallons treated with 21gal gumout complete treatment for a few hours now, and it doesn't seem to be improving. That cleaner is capable of removing water as well as treating the system.
- Compression test
- all cylinders are building within 2-3 strokes to within parameters. All cylinders are behaving the same way, too, so one would expect that both sides of the engine would be misbehaving, not just one.
There are no other codes getting pushed, and I do have a scanner capable of giving me live data, although I really don't know what to do with the data it's giving me, tbh.
The only thing I'm noticing is that the EVAP canister purge solenoid is repeatedly ticking something awful when it's told to open, just ticktickiticktick the whole time it's open, and it's loud.
I'm at a loss, and wondering if someone out there might have an idea of what to look for next. Thanks in advance, and comment if you need more info - I'll get it ASAP.