I've had an intermittent check engine light for a while, and it wasn't causing drivability problems. Lately the mileage went down, and then it started to run rough. I figured maybe the O2 sensor, so I checked the codes and found 32 and 35 (O2 and Purge Valve). I checked the purge valve and it seems to be fine. I bought a new O2 sensor at Autozone (Bosch universal) and installed it. Cleared the codes by removing the ECM fuse. When I started it, it ran up to fast idle fine for about 15 seconds and then died. I tried it several times with the same result. I connected the black OBD connectors again, and now the CEL just flashes continually. I checked continuity on the O2 sensor lead, and it seems to be OK. I could use some ideas.

Did you check the reading of the new code? May not be the same codes as before. I would check the areas you worked near while checking the Purge valve and installing the 0-2 sensor you may have knocked a vacum line off or unpluged something.

I've had an intermittent check engine light for a while, and it wasn't causing drivability problems. Lately the mileage went down, and then it started to run rough. I figured maybe the O2 sensor, so I checked the codes and found 32 and 35 (O2 and Purge Valve). I checked the purge valve and it seems to be fine. I bought a new O2 sensor at Autozone (Bosch universal) and installed it. Cleared the codes by removing the ECM fuse. When I started it, it ran up to fast idle fine for about 15 seconds and then died. I tried it several times with the same result. I connected the black OBD connectors again, and now the CEL just flashes continually. I checked continuity on the O2 sensor lead, and it seems to be OK. I could use some ideas.

Hm...what model and year is this Subaru? I don't know all the codes that can cause a flashing CEL but cam position sensor too out of sync with crank position sensor is one of them, which could be caused by a few different things.

Sorry, I broke rule no. 1. It's a 94 Legacy SI 2.2 AWD automatic. I got it running, and now it's throwing a code 35 again. It's backfiring and running rough off idle, but runs OK at higher engine speeds. I tried blocking the vacuum port the purge control valve pulls off of. That made some difference, but it still doesn't run right.

I would check for vacuum leaks. The manifold gaskets may be leaking. Check to see if the purge valve has continuity. The coil may be open.