Questions and Answers

Ob-NOX-ious Chevy G-10 Van Q. Dear Mr. Vincent Ciulla, I have high Nox Please advise me the solution. 1989 Chevy G-10 Van 4.3 liter Automatic transmission 140,000 miles Fuel injection Thanks, Jag

A. The first thing to check is the operation of the EGR valve. This valve re-circulates spent exhaust gases back through the engine to be reburned. This process also is designed to lower exhaust gas temperatures which is the main cause of high Nox. There is an EGR valve, the vacuum line to it and the EGR solenoid, as well as the ECM (computer). If all this checks okay you will most likely need a catalytic convertor. If that is the case put a new O2 sensor in it as well.