see the "expected gas mileage" thread for more info, but not really needed.
The jist is my car vibrates at idle, only in drive, and now it seems only with the brake applied...
I was doing some experiments today in regards to this problem as it was raining so i couldn't do the final mount.
interesting:
with the car in drive and the ebrake on and my foot off the brake pedal, it sits perfectly fine at idle rpm and pretty smooth.
as soon as the brake pedal touches the switch under it (not even actually applying brake pressure) I get a sharp momentary voltage drop and rpm drop on the gauges and the car starts to vibrate. as soon as the pedal is off that switch, no vibration.
curious. some sort of electrical problem?
ill try and get video tomorrow if needed.
There should be 2 switches. One for the brake lights and another for the Cruise Control shut off. If you are feeling frisky, you can disconnect them and manually operate both without moving the pedal to isolate which one is causing the grief. If neither is causing troubles perhaps you have a bad brake booster causing essentially a nasty vacuum leak.
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I think you have a vacumm issue.Granted I will go as far to say it is a map sensor that maybe fluctuating(but want swear to this).I replaced every single vac line on sunny couple years ago on my intake gasket job/repaint block job.My car has rubber and plastic vaccumm lines the plastic ones go to the air cleaner and this is sold at auto zone,advance in case you wonder where to buy.I would check your hose from the booster(brake) and even go as far as removing it for a true inspection.If anything I said is off grant me a pass being well tired and 538miles of driving and a 12hr day.Unless your torque convertor is acting stupid or tcc switch is this might apply to the shake.
I think we are getting close now...
Depress the switches without the pedal one at a time and note results. Then brake as normal. I think you are going towards a vacuum issue, but lets see what your results tell us.
Keep it coming
It could also be a carbon build up issue in the throttle body. If you excessive buildup the IAC cannot adjust properly . There should be a very defined line on the pintle of the IAC all the way around. If its fuzzy or has any breaks you will have to clean out the assembly. In severe classes I suggest consulting a shop that uses BG products it will remove that crap like nothing.
Not sure but I thought the cruise also had a vacuum line feeding up by the brake pedal that dump cruise control vacuum when the brake was used to disengage the cruise. You could try temporarly plugging the vacuum line that feeds the cruise and A/c Controls.
