odd revs and engine buzzing

[cleong]

Hi guys. Had something weird happen today. With the car in drive and the brake pressed the engine started making a rumbling / buzzing sound. Also i can feel a vibration through the brake pedal. It kind of felt like the engine was straining against it. While in drive the RPMs were around 1000. Once the car was moving it would go away until I hit the brakes again

When I put it into neutral or park the RPMs jump up to 1500-2000. Once I turned the car on and off everything went back to normal.

Not sure if this makes a difference but I was driving in traffic when this happened.

[LittleHoov]

Any lights on the dash when this happens? Did it feel like the brake pedal was "fighting" you? The first part simply sounds like the ABS system engaging, were you braking hard at the time?

Not sure about the high rpm thing, thats just weird.

Id give the brake system a quick once over, check the vacuum line running to the brake booster, check your brake fluid, etc.

[cleong]

It does feel like the engine was fighting the brakes but it was pulsing like how it normally would with the ABS engaged. Definitely wasn't braking hard and just recently had the brakes checked out when i had the pads changed.

No lights come on when this happens. In fact except for the revs the dash looks normal.

[LittleHoov]

The only thing that comes to mind is to check out all 4 of your wheel speed sensor wiring harnesses. They will be mounted on a little clip just behind the wheel bearing.

In my experience, sometimes they would fall off the clips and be hanging there.

The ABS system is very sensitive when it comes to the voltage from the wheel speed sensors...its supposed to be...so when they hang, or flop around, or the connections are dirty or corroded, it can sometimes make the ABS engage when its not necessary.

It doesnt always throw a light either, I had some brief issues with this, caused me to nail a parking curb one day, and nearly rear end another car another day. It was both low speed, not hard, braking, but the ABS "fighting" me, wouldnt let the car stop.

I pulled, cleaned, and reconnected all the wiring connections at the wheels, and went so far as to zip-tie the front two harnesses to their mounting clips, because they were the ones always falling off.

Something to try at least.....