Need help CIS or more
 

I have a 1982 911sc 100% stock. i was getting ready to chase down an air leak then--- i drove to work and back 72 miles each way. got there no problem still hunted rpms little after warmed up. i started car to go home little puff white smoke at start up. went away in sec. i drove home. pulled up to the house and the idle was 1000 and bouncing up and down to about 0 . up and down. i noticed that the lights dimmed as it went down and as it got to 1000 rpms the lights were normal.
the next day i started it, it started right up idled at 1200. i did not have time to drive so i turned it off. started it three more times started great..
what i have done so far plugs,wires,cap, and rotor. the old cap and rotor were bad burnt up. i changed all this before the problem started...

not sure where to start. the lights dimming has me stumped. thanks ....carl

ps. looking at the plugs looks like it might be running a little rich

if the RPM's drop low enough, the lights can dim. you can always put a multimeter on the battery with the car running or take it to advance and they will check the battery and charging system for FREEEEEE!

surging like that is usually caused by too rich a mixture, due to bad fuel fuel pressures. NEVER adjust the mixture until you have at least checked pressures.

first is to check for air leaks and check fuel pressures.
you can get a smoke test done to check for air leaks, or just replace anything rubber that has vacuum on it. including injector sleeves,seals and intake runner boots.

you can also check power to the WUR, check an make sure the frequency valve is vibrating.