Slow idle with lights on

[iMacThere4iAm]

I've noticed lately that Felicia idles somewhat slower and rougher with the headlights on or other electrical load such as the fan. Is this normal or a sign of alternator troubles?

 

[malcolm]

I'd say it's a normal sign that the alternator is working - it wouldn't load the engine if it was broken. Electrical load does put a lot of load on the engine.

What idle speed are you running? If it's too low the electrical load will make a lot of difference. Otherwise some other malady.

 

[iMacThere4iAm]

Okay, that makes sense. I'd not be very surprised if my idle speed is lower than it should be - I have a tachometer but Ive not tested it yet.