Cylinder 4 Misfire for 2003 Baja non-turbo

[bpridgen1124]

PLEASE HELP!!! I have a 2003 Baja that has an illuminated CEL. The mechanics at the local Subaru dealership seem to be baffled. The code is showing a "misfire" (chamber 4) iCode 304 I believe, in the ignition system but no other info is available. Here is what hsa been done so far...

-New Plugs/wires are new as well as the coil
-Re-flashed computer
-Cleaned injectors/ switched injector 3 and 4 to see if code would follow to chamber 3. Code remained w/chamber 4
-Cleaned carbon out from behind plugs
-Replaced timing belt and reset timing under advisment of dealership

After about $2000 in parts and labor, the CEL light remains. I have noticed that the engine will surge somewhat at about 3500-3900 RPMs at which point the CEL will blink. I am at my end at trying to pinpoint this problem...if anyone else has had a similar issue PLEASE let me know. Any ideas?????

Thanks,
B.

[adm_wiskyky]

Any luck troubleshooting this one? I seem to be having this problem now.

[hocrest]

Have you done 1 and 3 from the above list?

[TastyHuman]

Do you actually notice the miss or is the only evidence the code? Does it always miss or is it just under certain conditions. Hot? Cold? Under load? During acceleration?

We chased a problem similar to this on a 94 Taurus SHO once. It ended up being a single sensor wire that had been exposed to high heat too long and the resistance had increased to the point where voltages were affected. That piece of wire caused months worth of grief.

I'd take it to an independent shop that might actually troubleshoot problems instead of throwing new parts at the problem. Seems like a skipped timing belt would affect timing on all cylinders, not just number four.

I look for AAA shops because if you aren't satisfied they will run interference for you.