1996 Chevrolet Corsica Brakes and throttle issues

JAZZYJAZZBO

MEMBER
1996 CHEVROLET CORSICA
102,000 MILES

2 issues with a 96' Corsica my wife drives.

1. Brake fluid is disappearing, or so it seems. About once a month the brake light will come on and I'll have to add a small bottle of fluid. The brake light will gone once cracking the car again until about a month later when the cycle repeats. I can't find a leak anywhere (all the lines look clean, nothing dripping, and no drips on the garage floor where it's always parked).
Is it a small leak I just can't find, or would anything else cause this? (Need to bleed the system again, need a new master cylinder, etc.)?

2. The other issue is the throttle "sticking" so to speak. When the car starts up it idles perfect, occasionally though during a drive it'll start idling about 1,000 RPM higher and not drop below that RPM (in park or in gear). The only way to stop it is to shut off and restart the car at which point it'll idle perfect again (until it randomly 'sticks' again). My only real guess has been the TPS, but that was replaced about 3-4 months ago when this was happening before. It started acting up again just about a month ago though, so I'm not sure if the new TPS was fried too or something else is really the issue.

. Any ideas?

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Have you checked the MC to see if it is leaking? Check inside the vehicle under the dash where the push rod goes through the firewall to the MC. See if anything is wet there.

As far as the idle issue, have you checked the idle air control valve (IAC)? The IAC is responsible for maintaining the engine's idle speed. Also, check for vacuum leaks.

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Thursday, October 24th, 2013 AT 7:41 AM

JAZZYJAZZBO

MEMBER
2 POSTS

Thanks for the reply.

I've checked the MC under the hood, around each caliper, and all the lines I could see for leaks, but haven't looked under the dash yet; I'll be sure to do so soon.

I found the record of the last mechanic visit as well when it had throttle issues to revise some previous info. It was March of 2013 (7 months ago) when it last worked on. The throttle body was removed and thoroughly cleaned, fuel filter replaced, and he installed a new IAC (not TPS as I thought).
With that said, should I go ahead and replace the TPS and/or might I already need another IAC too?

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Friday, October 25th, 2013 AT 6:19 AM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

I doubt the IAC is already bad. Remove it, have someone turn the key between off and on (don't start the engine) and see if the pintel is moving. Also, check for vacuum leaks.

As far as the brake fluid, if it is dropping in the MC, you have to have a leak somewhere. Keep in mind, as the brake pads wear, more of the fluid leaves the MC and goes into the calipers. However, that usually takes a long time to happen.

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Friday, October 25th, 2013 AT 5:16 PM