2002 Chevy Monte Carlo SS – engine misses, almost chokes

Dear Doctor: I am the original owner of a 2002 Chevy Monte Carlo SS with just 48,000 miles. The car runs fine at low speeds, but when hitting the passing gear, the engine misses and almost chokes out. When in neutral and revving the engine to 4,000 rpm, the same thing happens. I got trouble code “low air flow,” so I changed the air filter, fuel filter, and cleaned the MAF sensor. Any other suggestions? Mike

Dear Mike: The technician will need to hook up a fuel pressure tester and scan tool and monitor both while on the road test. A common failure with this car is a partly blocked catalytic converter. The technician will remove the oxygen sensor in front of the catalytic converter and measure the backpressure. Any backpressure reading above 1.5 pounds when the engine is raced to 3,000 rpm is too much and usually indicates a restricted exhaust. Do not use a cheap aftermarket replacement catalytic converter. Use either a factory GM replacement or direct fit Walker brand.

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