Hi everyone. So this has been something that it has been doing forever, but I figure I should ask some questions to maybe figure it out. At Idle, especially at night, I can see the cluster and the head lights fluctuate in brightness fairly rapidly. While driving or revving, no problem. With my fairly nice fluke digital multimeter I measure between 13.5 and 14.2 volts on the battery, bouncing around between the two. My battery is an optima, never a problem starting. Always tests well over 12v with the car off. My voltage regulator is a year old (crapped out on me once). I have a few of those bosch alternators floating around. Would it be possible that the alternator is the cause?

Heres some more stuff...
The car has sort of a random miss at idle. Not terrible, but enough to be annoying. The misses seem to follow the dimming pattern slightly. So far I have installed new, correct plugs, wires, cap, rotor, injectors, and I cleaned that suppressor disk up. My fuel pressure is good and I've installed a new fuel filter. I replaced the EHA and to my crude understanding of how this system works, I have adjusted it correctly. It feels like at points, the alternator puts a significant load on the motor. The Ac compressor pretty much robs all of its low end power. My low end power really sucks, but I can pass someone going 70 like its nothing. My city mileage is terrible, but I get almost 27mpg on long drives. My exhaust in general smells very gassy. I also didn't pass NOX. The guy said I need a new cat, which I believe, but I think there is something else going on and I don't want to muck up a new cat.

I guess what I'm wondering is, is the alternator causing the engine problems, or the engine causing the voltage weirdness. I've run out of things to try that I know of.

By the way it is a '92 2.6. Thanks for any suggestions!