need help, 91 camaro rs 3.1

[redcamaro04]

for awhile now my camaro has been stalling out on me when i press on the brakes...when i press the brakes my rpm's bounce a little high and then they drop and it stalls out, while im driving, in park, or in neutral...i've changed egr valve, iac valve, pcv valve, fuel filter and pump, i have changed vacuum hoses...its been doing this for 3 weeks now and i dont know what else to do...and the engine does not give me any codes...i want to thank you guys in advance for any help you give me......

[wrightz28]

good possiblity the check valve on the brake booster vacuum line is caput.

[redcamaro04]

ill check that out...thnx