shutting off

My friends 94 Grand Am Quad 4 we just gave her a tune up cause we thought this would help but any way the problem being that when you start the car and press the brakes the car shuts down it will start right up and idles fine but step on brakes to put in drive or reverse and it shuts down i checked the hose to the brake booster and looks ok, Cant figure it out why it does this. Any help will be appreciated thanks. FrankC :banghead:

Does it have cruise control?

no it doesnt have cruise control. You know its wierd cause it starts right up and idles fine but if you step on brakes car starts to shake and when you shift into gear if you hold the brakes then it shuts down.

try unplugging the vacuum line to the brake booster and plugging it, start the car and see if it happens. It sounds like a leak in either the line or the booster..

tried it still shuts down i checked the vacuum hose and looks ok, also the abs light is on know would that have something to do with it.

You should goto autozone and see if they can pull any codes.. that is if you can get the car there...let us know if you can

Try this: with the car running at idle, spray carb cleaner or wd40 around the intake where the throttle body meets the intake manifold. It might be a bad gasket, and that one is easy to replace.

Just a not make sure autozone uses the book to look up your codes not the computer the book is accurate and the computer has been wrong 4 times on me. DON"T LET THEM USE THE COMPUTER LISTED CODE MEANING make them look it up in the book that came with the scanner they told me 1651 was Power steering pressure switch. 97 grand am doesn't have a power steering pressure switch thats a ford meaning. the right one from the book was Circuit 1 fan relay problem translation ECM is blown.

Thanks guys for the info havent been able to check it any further working long hours but as soon as i find out what it is i will report back. Thanks FrankC

sounds like a vaccum leak. when you press on the brake the booster may be taking the vaccum the engine needs and causing it to die. try checking the vaccum line on the MAP sensor. may have pulled it loose when removing the cover thingy that the direct ignition thing is on.