89 GP Stalling Problem
 

Been working on a friend 89 GP, it runs pretty good, but has problems with stalling at idle, starts right back up, and the "check engine" light is not on while it's running, trying to figure out what could be causing it, i noticed when you push on brake pedal (4 wheel discs) it feels spongy, even thou the rear calipers and pads are new, fronts were still in decent shape, would a bad brake booster, or the check valve that connects to the booster not working, cause a stalling problem?

If was stalling and you had to wait awhile to restart I would have to say it was a crank sensor. But if it starts right up it would suspect an IAC motor. If the booster was bad your brake would be hard because you have no assist. I had a 94 olds cutlass supreme (same body style) and when you hit the brakes intermittently would go hard and no assist. I would try to bleed them agian.