power windows causes drop in engine power?

[jmfranc]

I was idling my 2.7L '99 4runner and put both of my back windows up at the same causing a drop in RPMs - is this normal? It happened with the tailgate window as well. Odd?

 

[KellyJ]

I have always wondered what the deal with that is also. I think it has something to do with the alternator?

 

[4Evr4RunN3R]

Yea mine does the same thing to. I just never figured out why?

 

[wizzells]

If this is happening at idle for you, it's normal. Reason being is that the alternator isnt charging much, if at all, at anything below 1500 RPM. Once it gets above that you would see the output of the charging system be something in the neighborhood of 14 volts. It will vary from car to car depending on the design of the alternator but every car I've owned has done this