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Topic: Engine idle goes up when braking... (Read 2418 times) previous topic - next topic

Engine idle goes up when braking...

I've noticed lately that my idle goes up a bit when I brake at stoplights, or wherever. As if it "revs" on it's own.  Is this anything serious ?

I also notice sometimes when I start the engine it goes from turning to just running, like it "skips" the actual startup .....

Thanks for any help :)

 

Engine idle goes up when braking...

Reply #1
Codes?
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Engine idle goes up when braking...

Reply #2
vacuum leak at one of the t's or hose to the booster?

Engine idle goes up when braking...

Reply #3
Quote from: BornInAFord;427819
vacuum leak at one of the t's or hose to the booster?

More likely the booster it's self, any leak in the vac to it would cause a continual high idle...

Engine idle goes up when braking...

Reply #4
Is this anything serious ? I am running stock manifolds to a y pipe with no cat, to a pair of flowmasters that are dumped at the axle. I was planning to replace the manifolds with headers and an h pipe, then possible a pair of Stinger tailpipes.

Engine idle goes up when braking...

Reply #5
Before you go on tell us if you have something called Emergency brake off

You ever remember hearing a rather annoying hissing noise kind of like underneath your steering wheel?

Engine idle goes up when braking...

Reply #6
No I never heard anything like that....I just sounds like the engine idle going up a bit. Could this be a transmission issue ?

Engine idle goes up when braking...

Reply #7
your brake booster is probably leaking. causing low vacuum pressure, so the car idles up to try to compensate for it.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Engine idle goes up when braking...

Reply #8
Quote from: Gary3072;427865
Is this anything serious ? I am running stock manifolds to a y pipe with no cat, to a pair of flowmasters that are dumped at the axle. I was planning to replace the manifolds with headers and an h pipe, then possible a pair of Stinger tailpipes.

double check again,,,
look at the brake pedal metal bar,, and follow it up to around its pivit point.
you will see the little switch the metal hits to make the tail lights illuminate.

if you see a vacuum line going to a plastic pluger device,, note it.
start the car, push on the brake with your hand,,, listen for a leak around those vac lines.

its either your "automatic emergency brake off" feature or the brake booster,,, or the booster itself,, or that 90deg fitting going into the booster which i believe is a spring loaded one way check valve.