Acceleration problem

[Bob Bewalda]

My 92 LT1 accelerates like the vacuum advance is not working, if it had one. It runs a steady speed ok, but when I want to speed up, it misses and sounds like its pre- igniting. If I kick it down, ( automatic) it will accelerate and maintain speed with no missing. Any ideas? Fuel pump is new 500 miles ago.

 

[geekinavette]

Not sure if the LT1 has a vacuum-assisted FPR...if it does, that sounds like "maybe" a fuel pressure issue. When you go WOT the VAFPR could be increasing pressure just enough to prevent it from starving for fuel.

Could also be as simple as a fuel filter?

Bill

 

[jmccloud]

Miss on accelerate

I've had 3 GM cars that had your symptoms, fortunately not my '95 Corvette.
In all cases it was a bad plug wire that caused misfire under moderate acceleration (especially if the torque converter was locked up and starting up a slight grade). The first one cost $100 at the dealer to diagnose one bad wire. Yes, they replaced only the one! After that, it was a new plug wire set installed in my driveway and problem solved.
To confirm, raise the hood at night in a dark area with the under-hood lamps disconnected and look for sparks. If there are 'auroras', get a set of wires.