glava2876

My car is running better than ever ...except for one intermittent problem. It idles great, runs smooth, but when I down shift through the gears it sometimes stalls as I am letting off.
It said something in the 84 Corvette brochure that it has a down shift fuel shut off programed to help gas mileage.
Could this be the problem child and what does the system use to shut off the fuel and manage it?
Not sure if any other 84's have this feeling, but even if it doesn't stall, when downshifting it feels like it decelerates to a point and then has a little RPM bump and then it feels normal -I may not be describing this very well.

FOURSPEEDVETTE

I don't think there is such a thing as a "down shift fuel shut off" programmed in. There would be no reason to shut the fuel off just because you are down shifting. That most certainly would cause the car to stall becoming a real safety hazard. Not something that would be programmed in for any reason including fuel economy. Have you replaced your fuel filter?

fredd1

One possibility, if you're very low on fuel the gas may be sloshing forward in the tank on decel. and starving the fuel pump. Just a thought.

glava2876

I had never heard of this and maybe it didn't go to production, but on page 38 of the 84 Corvette sales brochure it states;
"When you're cruising down the highway, ECM provides a set of instructions to the TBI and transmission overdrive to enhance fuel economy. And, when you are decelerating, the TBI gets waste reducing fuel cut off signal which totally shuts down the engine (without your sensing it) until a programed lower RPM level is reached".
If that is the case and something isn't performing correctly, my thought is that at the lower rpm it sometimes doesn't get the resume fuel message.
So here are my post questions;
1) I changed the chip to a Hypertech chip about 3 years ago, but don't remember this being an issue then -but wondered if it could be going bad?
2) Or could the ECM be acting up?
3) Or wondered if there is some sort of valve in the TBI that gets the signal to shut off the fuel and that part is going bad.

The fuel filter and sock on the fuel tank pick up have been changed within the past year.

glava2876

no, actually filled with Sunoco high test