Question 84 C4 flatspot

[Dom]

Hi Fellow Corvette owners.
I have an 84 C4 and am wondering if anyone has had this problem, when I'm sideways around a corner or just cornering hard the engine seem to have a severe flatspot under acceleration, with a full tank of fuel it's as if it straves for fuel but in a straight line it's fine. Gets off the line well but out of a corner it flatspots..
Any suggestions??
Thanks.

 

[936spdvert]

I have a 93 LT1 and do notice the same problem with closer to half a tank. If I hit er hard in 1st or 2nd cornering it pulls then drops like I stepped off the pedal then goes again. My guess is we have tiring fuel pumps. Could be wrong thou

 

[LE BARON]

Sounds like you are sucking air as the fuel goes to one side of the tank.
Not fun but you might have to drop the tank to have a look at the uptake pipe. Might as well change it while you are there and make sure it is positioned right.
Don't know if there would be baffles in the tank that could have come loose???

 

[Dom]

Thanks guys
As far as the fuel pump being tiered I would agree however the fact that it's works fine under acceleration in a straight line revs out in first second and third makes me think it's fine...

And sucking air?? I would say no, as the tank is full but I will check the pickup line that seems to be the only thing left to check, I've checked fuel pressure and can't fault it.

 

[LE BARON]

Had a problem a long time ago when an RV would sputter an die going up hill (over a bridge) but only when the tank was down around 1/2. OK when the tank was full. Didn't happen on flat road . Guy never went too low for it happen.
Ended up that the fuel tank was dented and the uptake pipe displaced so that it sucked air going uphill when the tank was less than full. Bring it down to a flat surface and problem disappeared. Changed the fuel tank and problem solved.
Sounds to me you have something similar as you are OK when full but problem occurs at some point below that and only when banking the car. Hence fuel displacement to the side of the tank.
You have eliminated the fuel pump so might be time to go a bit deeper. IMHO
Logic usually prevails when you get these problems.
Unless you have an electrical problem and the tank shifts a bit and cuts the voltage to the pump.

 

[VikingTrad3r]

before anything, both of you can grab a fuel pressure tester and hook it up to the schradee valve on the fuel rain and tape it to the windshield and drive it. recreate the issue, and watch for a drop in pressure when symptom occurs. Im not sure if the 84 has a port.

possibly the fuel sock ....