rough idle during braking

I just installed a new starter in my 91 RS camaro because my old one was dying. no problem with starting now, but after I drove it and was approching a stop sign I stepped on my brake pedal my car decreased in rpms like it was going to die, the rpms first drop down then it shot up. When my foot was completly down on the brake pedal it came back to normal. Does anyone have any idea on what causes this to happend.Sure will appreciate the input.

Are you sure that it's related to the braking? Did it just start doing it after you put the starter in?

It sounds like a sticky IAC, You could pull that out and check the operation of the spintle.. Also check to make sure the battery wire on your starter and battery is on good and tight, try turning the rear defrost on and see i the rpm's drop more than normal

It started doing it right after I installed the new starter. I rechecked the battery and the wire on the starter and they were on tight. I also turned on the rear defrost and the rpm's didint drop more then normal. I also installed a new IAC awhile back, and i just cant pinpoint the problem.

it's not really that un-normal for the engine to pull down a little bit when stepping on the brakes, unless it's really noticable. the brake booster robs a little vacuum. if it's really bad, i'd check for vacuum leaks

I have the same problem,and if I'm not a two foot driver, it will stall. Is there any help for this? I have a new rebuilt 4bbl Rochester and all the vacuum lines look good.

timing maybe?

Sorry for the delay, to many things to do. I replaced all of the vacuum hoses, that sure did take care of my braking problem thanks. Soon after that my car went out, so i had to replace my MAP sensor,alternator,fuel filter and battery. I also got a tune up done, now i have problems getting it started. When i turn the key the engine will sound like it wants to turn on but then it dies, so i keep trying till it starts.

Fixed the starting problem it was my pick up coil and module that went bad ...............