Help!

[911scporsche]

Hey all, I'm a new Porsche owner (1980 911sc) who needs some know how about engine electrical. The day after adding some Red Line fuel injector cleaner and running it for 30 mins on the highway, the car runs like crap. It idles reall rough (I know that air cooled engines run rough, but it is more than usual). It sounds like a 2 stroke lawnmower and sounds like (I don't know for sure) only a few cylinders are firing. When I turn the key to the "on position" the green light is on, but not the alternator (red) and oxs (red) lights. (maybe i need to retighten the fan belt?) I recently had the stater of the alternator rewound and replaced spark plugs and wires, as well as added a stereo and amplifier. Any help is greatly appreciated.
Cheers

Also I forgot to add that the tach was jumping all over the place (a sign that the battery is dying right?) so i shut off my stereo to conserve energy. Could there be some problem with the voltage regualtor not charging the battery? The thing is is that when I replaced the alternator and installed the stereo, there was no problem up until now... I checked all the fuses and they're fine...
When I step on the gas, the pickup (of rpms and power) is bad, teh car chugs along and seems to want to backfire? I noticed that it does start a bit rich ( lots fo gas odors after starting), but i don't want to adjust the fuel mixture without a carbonmonoxide sensor. The idle rpms are at about 900-950 so it's ok there...