94 Suburban Fluttering

Hi,

I have a 1994 GMC Suburban K1500 4x4 with a 5.7L V8 with Throttle Body Injection.

Ever since I got the truck, when I accelerate to say 1500rpm and hold the pedal, it will flutter, and when you let off the pedal it will almost stall but recover.

I checked it with a scan tool, it did not bring up any codes, but the O2 sensor was switching back from RICH to LEAN and back quickly.

I have changed the spark plugs, wires, distributor cap and rotor, fuel filter, fuel pump/sender, air filter, and cat back exhaust.

Thanks,
Eddie