"John A. Hage" wrote: 2003 Pontiac Vibe.
Occasionally, when I brake, the engine starts racing -
so much I have to push hard on the brake to keep it
from zooming forward. Usually (not always) if I shift
to neutral then back to drive, the engine quits racing.
Then I have to turn it off and wait a while, then things
are OK. The dealer couldn't find anything. Is there
anything in particular I should ask the dealer to check??
1.) These symptoms could indicate a cranky cruise controller.
2.) Braking action can also affect engine controls by upsetting
vacuum flow. The dealer might look for:
a.) Loose or leaking vacuum line to carb/FI is starved
by restore vacuum demand from brake booster.
b.) Disclosed crack in brake booster diaphragm drags
down vacuum until brakes are released or until RPM
is high enough to balance vacuum demand.
Wendy & John.