Engine dying out, help

I have a 1987 Sub. 350 4X4. I am havig a problem with the engine dying after I let off the gas at slow speeds. I have replaced all the fliters, plugs, wires, cap rotor, map, O2, fuel pump. It does not do it all the time, just once and a while. It runs fine other wise. Any thoughts? Thanks

Start right up and run ok?

Yes it runs fine. Highway is fine just once every few days it just wants to die out when I let off the gas, like the idle is not picking up fast enough to compensate for the drop in RPM. I had one person tell me I needed thicker wires and I was getting EMI, so replaced with 8mm, and I am not seeing an arching through.

Try cleaning the iac valve, disconnect the egr valve for a test also.

also check your tps to make sure it is not loose.

You may want to check your speed sensor if you have one on your transmission. A lot of times coming off the highway and jumpin off the gas to coast will kill the idle if the sensor is bad.