Only fluctuated during coast down such as to a red light/stop sign while in Drive, not at idle in Park/Neutral?

 

it didn't fluctuate when coasting. Just when coming to a stop it drops. It stays still in park and neutral. A little lumpy though....this may be a vacuum leak for that. I found a bad check valve at the brake booster in my other thread. Somehow, I still don't think this is the solution to my low idle.

 

Idle only fluctuates when your foot is on the brake pedal, transmission in Drive?

 

Yes.

 

So what is the common link to the brake pedal and idle?

 

vacuum I'm guessing.

 

Very possible.

 

Disconnect and plug the vacuum line to the brake booster and see if the idle changes. If you drive the car, remember that you will need to press the brake pedal somewhat more firmly...

 

Good call guys. I've seen faulty brake boosters do this to other cars.

 

Ouch. If it is, I am in for a $300 kick in the ***.

 

That's why you test it first, rather than throw parts at it initially.

 

Lot cheaper than an LH or standalone, now isn't it?

 

Yup. I was thinking about those 2 inlets on the 7-way splitter I bought that have no use that I plugged up. I am thinking of trying some vacuum line re-routes to see what affect it has on some of the HVAC controls. I think I saw a thread a while back on some vacuum line rerouting. I'm looking for it right now.

EDIT: Nevermind. It was unsuccessful in the thread.

 

If you disconnect and plug the vacuum line to the brake booster, you will instantly know if it is a vacuum problem with the booster, the HVAC system or the cruise control.

Quick, easy, free...

 

Just came back from doing it in the parking lot. Not the brake booster.