Hesitation on acceleration

[Chrispbrown36]

The stats....1987 Chevy V10 350 tbi auto.
Last week I finally got around to changing the spark plugs, wires, distributor cap and rotor. When I put it all back together I set the timing again (with the wire unplugged while I did it) and took it for a drive. The SES light came on and when I started to accelerate the truck would hesitate. For a whle now the truck has also been dying when I put it in reverse if I do not get on the gas quickly enough. After doing a little reading on here I took the EGR off and cleaned it up a bit and advanced the timing 4 degrees or so. The dying on reverse is still there but not as often and the hesitation is only there when I put it to the floor from a dead stop. The ECM is still throwing the 43 code but only if I stomp on it while going down the road. I have read that the 43 code is tough to diagnose because it can be anything rattling on or in the motor that is being detected, but I am hoping that my symptoms will point directly at something. Any ideas?
A little list of that has been done, but not necessarily in order to fix the current issue....just because I figured it was about time for it to be done:
new IAC
new map sensor
new cap rotor wires and plugs
new CTS
new oil sensor (can't remember what is called...the one behind the motor up near the distributor)
new valve cover gaskets and intake gaskets
new fuel filter