TNT

Well from a previous post some of you know I had a temp guage problem, it turned out to be a faulty temp sender. Purchased an AC-Delco replacement and volia it's fixed. Now for the next issue. When I press on the brake pedal while the engine is running, the engine RPM increase about 3-4 hundred RPM. It's a power brake car. Car has very good brakes. I'm thinking it's the check valve. Any ideas?
Thanks Thad

7T1vette

Most likely leaky seals in the booster. To check it, pull the vacuum line and check valve out of the booster and put some duct tape (got to be sturdy) over the outlet of the valve. Note whether the engine rpm went up or down from when the line was connected to the booster.

If the rpm is different when line is connected vs. when line is plugged, your problem is a leaky booster.