Engine sputtering on hard deceleration.

[Hammer Down]

So I did a complete 4 wheel brake job. Turned the rotors and drums. I installed new hawk hp plus pads and have some of their fancy slotted rotors. I flushed the entire brake system with dot 4. I also got new Nitto nt01 up front. Well, the car definitely stops better, I think about as good as it's gonna get with this setup. I'm happy. My question is when I was doing the brake in procedure for the new pads. 10 stops from 30, let cool then 3 hard stops from 40 then let cool, my engine would sputter and came quite close to stalling on the hard 40-0mph stops. Is this a fuel issue or vacuum issue possibly?

[erratic50]

What year is the car, how much fuel is in the tank?

[Hammer Down]

85, 3/4 tank fuel. Btw, it has a rear sump tank

[wraithracing]

85, 3/4 tank fuel. Btw, it has a rear sump tank

A rear sump tank could possibly be running dry on a hard deceleration and that might be your issue.

Vacuum could be an issue too depending on how much you have and if you have any leaks that might be adding to the issue.

You can connect a vacuum gauge to the engine and then tape it to the lower portion of the windshield in your field of vision. Then try some hard stops and watch the vacuum to see if it drops hard. If the vacuum is fine, then I would suspect fuel issues. You can do the same with an external fuel pressure gauge if you have one. Good Luck!

OH! Forgot with it being an 85, it could also be your float bowl adjustments in your carburetor too.

[erratic50]

If your idle is adjusted with a continuous vacuum leak in the booster and you slam on the brakes that will seal up the vacuum leak most likely. That absolutely could stall the motor. Plug the vacuum assist and see how it idles and acts.