Hey all, I'm still stuck on the surging idle problem with me ZC. Idles high (2k-1.5k and bounces down to 700). I've noticed that when I have the breaks pressed I can faintly feel the pedal moving up and down with the surging.

Also, if I quickly shut the car off after driving and pop the hood I can hear a hissing/suction sound coming from around the master cylinder for about 30 secs. I had to remove my alternator a while back and loosened up the cyclinder, but I've had the idle problem before this.

Can anyone help me out? I've asked for help on this idle problem before but can't seem to figure it out.
I've cleaned the eacv, but havn't replaced.
Recently replaced radiator, flushed and replenished coolant.
Cleaned TB.
New Fuel filter
Changed plugs..


also, I used to have some hesitation between 2k-3k on slow accleration. Its was getting pretty annoying, but I replaced my alernator and battery recently (both toook a ****) and the problem seemed to practically disapear, but it still does it mildly every now and again.

thanks

 

Yep, sounds like the brake booster. Pinch the fat vacuum line to the booster and see if the sucking sound stops. I think I paid about $60 for a rebuilt one from Autozone. The master cylinder has to come off to replace it - that means bleeding all the brakes when you're done.

 

I'd say it's the brake booster, but also check the booster check valve. I'd do a booster check. It sounds like it's bad.

 

Hey, thanks guys.. I'll prolly get to checking it out Sunday.