Idle dies when pumping brake

[MIghtymax89]

Hi everyone,
Another problem just occured and i would like to get some help. I just installed a tachometer on my truck to see where my idle is at. My idle is at 1,400 and fluctuate 300-500 rpm . it won't idle any lower, if it goes below 1000rpm it will just die . The diagram under the hood says it shd be idling at 700.

I keep dying at stop lights/signs and was wondering if it was the a/f or the idle screw. Then i started pumping my brake at idle and it was causing the idle to drop.

I read something about it could be the alternator/brake booster/ vacuum leak that cause it to die. so now i just be easy with the brake and im good with the idle. it still flucuate but lower.

I'm thinking of plugging some vacuum hoses that is really unecessary.

Other than that, The truck runs good.

[Fordubishi]

I had a problem almost the same with a customers cars, ended up being a small rip in the brake booster diaphram and when the brakes were applied it would cause a huge vacuum leak and kill the engine. Replaced the booster and fixed the problem.

[camoit]

yep thats it..

[MIghtymax89]

Thanks folks, Guess im going to have to do some saving for that brake booster then.

[Fordubishi]

not too bad. Napa has them for $107.00 reman. with $35.00 core.Just strip out yours and take it in so you don't get charged for the core.