Hi,

My Buick LeSabre Custom has 101,000 miles. I've posted about the rough idle and stalling in other posts.

In reading other posts online it is mentioned the brake booster check valve and gasket can also cause a vacuum leak.

When I push the brake pedal with the car running I notice a change in idle. It also seems that the majority of times it stalls is during or right after pressing the brake pedal. Could a leak in the brake booster check valve gasket cause this? The check valve seems to move pretty easily and the gasket looks worn.

The car has a constant rough idle. During hot weather the car will stall after idling for a few minutes. It doesn't do it constantly and it is only during hot weather after the car is fully warm and idling.

The plugs, wires, ignition module, coils, ECM, etc., have been replaced numerous times. The intake manifold was replaced along with the gaskets. The crankshaft and cam shaft sensors were replaced, the alternator, etc. The sensors check out OK.

Thank you.

After you shut the engine off, wait a minute and then remove the check valve from the booster. If you still have a strong vacuum there, there is no leak.

Thank you.