Xzavior1818

So Ive had my firebird for a month now and things have been alright until just the other day my car started acting funny. It seems to be a vacuum leak of some sorts because when i apply the brakes the car rpms go up to 800 rpms from 700 and when i let off my brakes my car stumbles to 500 rmps even stalling out sometimes. this is in all gears including park. its also worse when the car is warmed up. car runs fine other wise and i can drive it i just got to be gentle on the brakes when stopping so the car doesn't stall. my brakes feel solid and normal like any other car so im kinda left confused.

my ses light comes on & off at times too. but only when driving and not all the time..

its a 1990 v6 model.

map sensor?
bad ecm?
iac? (which i cleaned)
stuck egr?
bad brake booster?

antares57

iTrader: (8)

Welcome to the forum. I noted you told us what vehicle you have in the post. Please take a moment to update your profile so you don't have to keep typing it in. First, I would check what error codes are stored in your ECM. Your vehicle is trying to tell something is wrong. Second, if it's only happens when you use the brakes you may have a vacuum leak in the booster. You step on the brake, air leaks in, and car stalls because of too much air. Check your brake system for vacuum leaks. Lastly, tell us what you have done already to try and diagnose the problem. Don't forget to use the search function heavily, lots of info in here. Good luck.

maroe624

my 3.1 does the same thing except it doesnt drop that low or stalls. Check for leaks all around the intake with a small hose. Put one end to your ear and use the other end to check for leaks around manifold and throttle body. .

Xzavior1818

Yeah ima have to get the codes pulled. Im pretty sure this is a vacuum leak of some sorts. Ive cleaned the throttle body and checked the filters. ive checked all the vacuum lines for damage. I checked the check valve on the brake booster too. Car runs fine but like i said when i press the brakes the rpms dip alot. Im starting to think its a bad brake booster because this problem only happens when the brakes are applied. Running the heat, lights and ac dont affect the idle much. im gonna try to get an ODB1 reader and see how the computer is running under certain conditions.

project89

iTrader: (1)

u dont need a code reader , do a search for pulling codes with a paper clip , it will tell u all u need to know . id type it out for ya but im at work

Xzavior1818

Took it to a shop, they said its a vacuum leak coming from the intake manifold tee . they said it was cracked so i had to order a new one off the web. I ended up replacing the brake booster with a AC Delco re manufactured one. Mine did have a vacuum leak but the car still drives a lil funny so we'll see once the manifold Tee comes in the mail. I might as well replace the old vacuum lines anyway. they are looking dry rotted. Will update once i get it wish me luck

Xzavior1818

Well after a couple vacuum lines replaced and a new intake fitting, the car runs great!! problem solved!!