92 S-10 2.5L SURGING Problems code 32 EGR valve

[Jeepjones85]

I have a 92 s-10 2.5L That i have been having problems with.
After the motor has warmed up and i have been driving highway
speeds 45-55 it starts surging what i mean by that is you will be giving
it the same amount of gas and it feels like you let off of the gas like
it is being chocked down the only code that the diagnostic check is
flashing is 32 which is Vacuum switch shorted to ground. So i replaced
it and cleared all the codes and after a little bit of driving it does it again.
Also the Egr valve has been blocked off but the problem started before
I did this. Any idea what might be happening Thanks Rob!!!

[Chris Stewart]

Does it have the old vacuum powered EGR or the new style electric EGR?

The new style electric EGR feeds the EGR pintle position info back to the computer. If the computer sends a "close valve pintle" command and the EGR doesn't report that the pintle is in a closed position because it's blocked or stuck open or the wiring connector is disconnected, the computer will set a Trouble Code 32.
Now here's the sauce...if the Knock Sensors sense a knock, the computer backs the ignition timing off until the knock sensor hushes up. Can you guess what helps keep spark knock to a minimum? Yup, the EGR valve.
Seems the little bit of exhaust gases allowed back into the motor keeps the fuel burn from getting so hot which reduces spark knock AND the production of Oxides of Nitrogen...smog.
This doesn't help power production but when I wanted power, I built a 406 small block and put it in an early Nova instead of dogging out my regular transportation.

[Jeepjones85]

Thanks man I will unblock the egr valve it self and see what happens!
Thanks Again

[nstodghill]

Hi my truck was surgung also so I tried cleaning the EGR valve when I put it back on the motor was knocking very bad, So I put a New EGR valve on and it is still knocking bad and runs very rough. Do you think this is the same problem.