Stalling on hard braking - 86 Z28

1986 CHEVROLET CAMARO
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YZFRIDER
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Okay, anyone have this problem? I can sit out front of my house and get the car tuned just fine, it'll idle right at ~700 rpm. Bump the throttle, revs fine, comes back to 700 rpm. However, go take a test drive and as soon as you make a quick stop or a hard turn, the car can't maintain idle speed and dies (makes for some good exercise trying not to have an accident when the power steering goes away!). The gas mileage also is pretty rotten now, only around 15 mpg (highway). I had similar behavior with my original carb too (except that one leaked around the bronze throttle bushings too), so I don't think its a carb problem.

Here's some stuff I noticed:
- I tried a fast stop with the car in reverse and it didn't seem to want to die.
- If I sit with the front of the car down a hill that the engine speed drops about 250 rpm (if that helps).
- To make the car somewhat driveable (no stalling), I've got to keep the idle set between 1250 and 1500 rpm.

Does this sound like a fuel pressure problem? Too high? Too low? Maybe as simple as replacing the fuel pump?

I've got a fully rebuilt 305 (lightly modified, bored 0.030, hotter cam, etc.), a T-5 tranny, Edelbrock tubular headers and catback system, and a new Quadrajet carb.

Thanks ahead of time for any help!
Aug 6, 2007 at 7:57 PM
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DANIMALGMC
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Check your float level.
It sounde like it's set to high.

Lose the Quadrajet and get a nice Holley.
Quadrajet's are nice but all that work you did, I think a nice holley 650-750 would give you better performance.

Good Luck.
Aug 27, 2007 at 3:24 PM
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YZFRIDER
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Thanks for the feedback danimalgmc. I thought about a different carb, but haven't gotten that far yet.

Just an update for everyone. The car is spitting codes 14 and 53 now (so that's some help), one code is for a coolant temp malfunction and the other is for an EGR failure. I've done some reading and I think if I can take care of the coolant temp issue, this may help the EGR issue (I think this might be the root of my problem) since the ECM makes use of the coolant temp to help control the EGR vacuum solenoid. I'm guessing the problem is that I'm using a 170deg thermostat (put it in during the winter so I wasn't freezing) with a Hypertech Thermomaster chip that is supposed to use a 160deg thermostat.

I'll swap back to the 160 deg thermostat and see if that simple change helps. If it does, I'll let y'all know.
Sep 3, 2007 at 5:35 PM
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