S-10 Blazer warms, surges and stalls

[who_is_this43]

Well here is the story. 92, S-10 Blazer, w engine (orange cover), 189K miles. It atarted running poorly so I changed the O2 sensor and EGR, worked great for about 6 weeks. Driving home it started surging and wouldn't go more than 4 to 8 MPH, I had no where to pull over and was almost home, stalled but started back up pumping the gas. Catalytic converter was glowing. I left it at the bottom of the hill, it wouldn't have made it up. Came back a couple of hours later and it started and ran fine up the hill in 4WD. Drove it a few more days and it did it again. Starting it again it would run fine for a few minutes and start surging again about every second from 500 to 1500 RPM as it warms.

I changed the Rotor cap, button, plugs and wires and now it has a slight miss warming up before it starts surging. I have IAC, MAP, fuel filter and fuel pump and nothing changes. I did find some water in the tank when I changed the fuel pump but emptied it completely. Midas tells me over the phone the catalytic converter is not the cause and that some other problem caused the converter to glow and has to be fixed first. I have checked the vaccuum lines, it won't start if it stalls now unless I use starting fluid. So I don't think it's ignition. Fuel injector assembly was change 6 months ago. Any clues?

[Mikado14]

Check your knock sensor.

[Fireplug]

Glowing Cat sounds like a lean fuel problem. Whats you fuel pressure when its acting up???

[who_is_this43]

Well I'll be, the knock sensor seems to have done the trick, it's running fine now. Thanks, been looking for this problem for a week. I'll let you know if anything changes, crossing my fingers.

[who_is_this43]

most appreciated!