99 Camaro V6 codes P0301B and p0404

99 Camaro V6 automatic 70K miles with the following OBDII codes:

P0301B - misfire cyl 1 (anyone know what the B means?)
p0404 - EGR control circuit range/performance

SES light flashed (indicating the misfire) and stayed (must be for the EGR) on while doing ~70mph cruise. Following that noticed sluggish response when accelerating at 2500-3000+ rpm. Flashed again while attempting acceleration. After cold soaking, restarted and found SES light still on steady, but acceleration response returned.

Cleared codes and performed a drive cycle, EGR code returned but not the misfire. Now noticing sputtering at 1/2 and 3/4 throttle acceleration between 1500 and ~2700 rpm, with a noticeable increase in power at 3000+ rpm (stock engine, no turbos).

Other items: The fuel meter does not appear to be accurate and varies, at times by up to 1/4 tank Also noticed (rapid) voltage fluctuation in cold (< freezing) weather of 13.5 to 15.0; steady voltage in warmer weather with 14.5 at cold start, and 14.2 when warm. Not sure if these have any relation.


Any thoughts on probable cause?

I was thinking the EGR needs to be cleaned (or would replacement be a better option?). Could this EGR problem cause a single cylinder to misfire at least twice? I would think that if the misfire was related to the EGR then random misfires would occur. If not, than I was suspecting the spark plug and wire (esp considering GM's poor wire placement over and behind the engine).

Any other ideas? Is this a good approach? I'd obviously rather not put in parts and labor that won't fix the problem.

Thanks for the help!

Update: Cylinder 1 is misfiring again starting around 4200 rpm. I'm thinking the fuel injector? Have any ideas or other possibilities?