** I'm editting this three weeks after the original posting. I have put a summation of this problem as well as the solution and the other issues/solutions I have had with my Subie at the end of this thread. Maybe it'll help someone with theirs.
I'm working on my car that I bought used a little over a year ago. It's turning out to be sort of a project car, I guess.
I found a post here from 2006 that described what I have excactly, but I never saw a solution, so I'm trying with this one.
My Subie Outback sedan with about 205.000 miles runs like a top for about three weeks. Then, driving along, it runs crappy for about half an hour.
I recently had a purge valve solenoid/circuit code. I changed the solenoid and the code never came back. After that part change the car ran even better - runs really well.
Over the last year or so I have changed the plug wires/NGK plugs (from a misfire code), the engine temp sensor (with a a Subaru part for the ECM not the gauge - this took care of an idle problem), the TPS (to fix erratic acceleration - no code, but took care of it), recent fuel filter and fuel pump (working on the current problem), and map sensor (also guessing on the current problem). Also cleaned the grounds to the engine. Fuel pressure is right at 44 psi. Regulator has been changed.
It acts like it runs low on fuel, but never finally dies. It always catches and takes off again, then starts missing and dieing out, then catches and goes. This goes on for about half an hour, sometimes less. At full throttle I have full power. After a bout of this, it's fine for about another three weeks
I had the alternator checked recently for voltage, thinking maybe it was messing up the sensor readings I got a put out of a little over fifteen volts and thought that must be it. I found the alternator fuse was missing from the engine compartment fuse box. I put that back in and the voltage is down to about 14.3 now.
This is where I'm at now. Car running great, waiting for it to either keep running great or return to "normal"
Open to all suggestions,
Appreciate the help.
Edited by farmer, 19 April 2013 - 08:23 AM.