It's weird when I'm just at a light idling and press my brakes all the lights in the car become dimmer, like the a/c, radio, and cluster(this happens mostly at night when the headlights are on). I have HID's so i don't really notice if they dim or not...but when this happens i feel a slight vibration in the car, i don't really notice the RPM dropping. I let go of the brake and the vibration stops.

I cleaned my TB, IACV, and ran some sea-foam through the brake booster line. Just did an oil change and do all the maintenance on the car religiously. This is really bugging me out..

I don't have any re-wiring done or anything. All i have is an aftermarket alarm, the HID's and well that's it. I used a 30AMP fuse for the headlights because that's what someone recommended. I hope this is just something to do with grounding? If so I just bought some 0/1AWG wire to do my own grounding kit.

If someone has opinions, advice or anything that might solve this vibration let me know. Thanks.

 

bump...can anyone help me pin-point the problem plz..

 

What is the alternator putting out at idle and under load?

 

I actually wanted to test my alt a few days ago but the store wouldn't let me borrow a meter to check it out. You think the alt is on it's way out? Would it help if i ran a nice 0 gauge wire directly from the alt to the battery?

 

I notice my lights dimming also whenever I step on the brakes. Occasionally, the rpms will drop 100 or so and I will feel a bit of vibration, but it corrects itself after a second. Alternator would be my only guess other than bad grounding somewhere. Maybe our cars are just getting old.

 

thats funny. i almost have the same problem. when im stopped with my foot on the brake, when i turn the steering wheel, the RPM's rise up...... everytime i turn that wheel the rpm jumps up by 200-300..... also when car is stopped and if i put it from N to D while brake is applied. the rpms lower by 200 and the car starts gettin a bit shaky.......

nice avatar btw !

 

I think this is a good write up:

http://home.earthlink.net/~maxfaq/maintenance.htm#idle

I also experience vibration when the car is about to fully stop. I noticed the tach hitting ~650rpm(which is within spec) when in "P" or "N", but when i put it in "R" or "D", it drops down to 500rpm and i can feel the vibration in my steering wheel.

I haven't tried the stuff in the link above, but seems like a good way to attack this problem

 

Yeah, when i turn the steering wheel the tach seems to "jump" to the rpm level that it's supposed to be @

 

Yea, what is up with that? I get the same exact thing!!!

 

^what you guys are describing is perfectly normal...it your car isn't doing that then you have a problem. I don't think it's the alt but i hope my grounding kit helps.

 

yeah, it'd be a problem if the rpms didn't jump when switching from N to D, but it sems to be doing that about 150rpm too low.
We're talking about the rpm ranges, not the fact that they jump.