RPM fluctuation

[jcslocum]

This kinda sounds like a vacuum leak to me. You should begin looking at the rubber in the engine bay for cracks. On our 2000 we have been chasing vacuum leaks for 2 years and the brake booster diaphragm finally failed. it wasn't even on our radar as the source of the problem.

A smoke test would help locate any leaks.

[Gelbster]

Originally Posted by jcslocum

This kinda sounds like a vacuum leak to me. You should begin looking at the rubber in the engine bay for cracks. On our 2000 we have been chasing vacuum leaks for 2 years and the brake booster diaphragm finally failed. it wasn't even on our radar as the source of the problem.

A smoke test would help locate any leaks.

Very useful.Thanks for sharing.
This is why vacuum leaks can be so difficult to find yet easy to fix
.But first you need to find them. And the suggestion to just pinch off Vacuum Hoses at strategic points to diagnose does not work well for the Brake Booster !Nor does carb cleaner or propane.Maybe a smoke machine:
"Brake booster leaks: Disconnect the booster’s vacuum supply hose and introduce smoke directly into the booster (eliminate the check valve for this test). Check for smoke exiting the booster canister (crimped areas, etc.), and check underdash for smoke exiting through the rear of the booster (don’t depress the brake pedal during this test)."