Chevrolet Repair: 97 chevy cavalier, spark plug wires, chevy cavalier

Question
I own a 97 chevy cavalier, about 2 weeks ago I was going up a steep hill and my car lost almost all of it's power. It goes about 10 mph up a hill about 45 mph straight. when you start it, it sounds like it's missing or flooding itself out. we put new spark plug wires and spark plugs in it. but when we pulled them back out they were black. there is grey smoke coming from the tail pipe too. we changed the fuel filters and checked the throttle sensor and the fuel regulator. the engine does not hardly have a enough power to change gears.the car has never been mistreated since i have owned it, never been run hot,never had no problems out of it. It run fine until then. Always started easy. Can you help me? It has 121,000 miles.  

Answer
Sounds like an exhaust restriction. Most likely the catalytic converter. Run a back pressure test on the exhaust system and anything OVER 1 lb is an exhaust restriction.

What mechanical work or ANY kind of work has been performed on the vehicle recently ?. As most problems that occur after a recent repair was made can be traced back to the area of where the repair was made as a vacuum line may have been knocked loose or a wire connection came loose, Look around in the area where work was performed..

IF the catalytic converter gets physically RED HOT, This is a sign of in most cases an ECM (computer failure).



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