Rough Idle When Lights Are On
 

Recently, when I turn my headlights on and my car is warmed up and I am driving, my car will start to idle rougher than without my headlights on.

Can anyone tell me why this might be?

Also, I have yet to get my 30k service yet, so I know I need new plugs/wires/coils...

^just paranoia, i dont see how that would affect anything, your idle should smooth out when the new coils/plugs/ and wires are in

I can sit in my car right now and if I turn them on, my idle RPM's drop down, and if I turn my headlights off, then go back up to normal though...

along with the coils and plugs also try cleaning the MAF if it looks dirty--- This wouldn't hurt

Sounds like there is a power drain or some kind of extra electrical load on the motor.

Any problems starting the car or have you replaced your battery within the past couple of years?

Normally the idle will get rough if it gets much below 750 rpms. I know I get a bit of an idle hunt in the summer time with my AC on.

what year is it, alternator could be putting in overtime.

I just recently cleaned my MAF a few weeks ago.

Turning my car on when it is cold is not bad but if I go in out to eat or somewhere and 10-15 if I try to start my car it takes 3-4 seconds for it to start, which worries me.

I have only had the car for a few months and the battery has been fine as far as I know.

During the summer I never ran my A/C because it stalled on me twice with my A/C on...

And it is an 2004 Automatic RX8.

You need to check the voltage under load. When my lights turn on I lose about .3-.4 volts but its doesn't affect idle. If yours does then you have electrical issues, have your alternator and battery checked.

^ Now I'm thinking electrical too.
AT's while in gear and using A/C or defrost tend to run rougher at idle. Check your voltage, I'm thinking your alternator is toast or the change in seasons has your battery working harder to the point were it's telling you it's time for a new one.

^ Now I'm thinking electrical too.
AT's while in gear and using A/C or defrost tend to run rougher at idle. Check your voltage, I'm thinking your alternator is toast or the change in seasons has your battery working harder to the point were it's telling you it's time for a new one.

Oh, assuming that the battery could be the oringinal from '04. The battery should change anyways. If you get 5 years out of a battery your ahead of the game ( I know your the second owner) 3mo. is a lot different then 5 years---- sux man

What was the picture of? It shows the photobucket bandwidth thing.

So I should have my alternator and battery checked to see if that is the problem?

1. Check your spark plugs
2. Check your batterie
:yesnod:
GL

Yes.

And your alternator. When the car is driving, it is the alternator that powers everything, not your battery.

Could be one or more coils is marginal, since you plan on new ones, try that first. If that doesn't fix, then check alternator. If alternator output is ok, may be a grounding issue.

alternator could be giving up on you maybe ... what i noticed on my 8 is that it takes like 5 seconds to start it sounds like the battery is weak but is not it does this each and every time since i git from the dealer they said it was normal on these cars i also live up here in seattle so the cold doesn't help at all ... any of you guys experiencing this??

i've seen other 8's and they start right away

ps: mines is an 05,i recently replace the spark plugs myself

thanks

Alternator's are not cheap to replace are they?

I got mine with 6k on it from a junkyard on eBay for like $60.00. You can get your rebuilt for about $100.00 but rebuilds don't tend to last so get a warranty.

Does the alternator count towards the extended warranty that Mazda made?

I bought the car used so I do not have an original warranty with the car.

try to stick with an original mazda alternator, junk yard, or ebay has several listed. easy install.