Questions and Answers

GMC 1500 DTC 32 Q. I have a 1994 GMC 1500 with a 5.7 liter V-8 and automatic transmission. I recently installed dual exhaust from the manifolds back, removing the catalytic converter. The oxygen sensor was reinstalled in the right pipe. The problem I am having is the Service Engine Soon light is now appearing on occasion. The scan tool that I have purchased shows a code 32 "Exhaust Gas Recirculation (EGR) Error (Back Pressure)".

I have replaced the solenoid for the valve, with no success. The valve itself is good. Any suggestions would be appreciated.

Thanks,
Ted

A. You will not like my answer. The EGR relies on a certain amount of exhaust back pressure to work properly. Now that you have lowered the back pressure, it can't work. Have you tried a new EGR valve?

You may need a service manual with an EGR diagnostic chart to make sure, but I think the duals are the problem. Plus the O2 sensor is only looking at one side of engine instead of both.