2002 pontiac grand am 3.4 Catalyst not ready no codes, no check engine light is on

SOURCE: 2002 pontiac grand am 4 cylinder sedan cant pass emissions

not enough information so i will cover many possibilities:

new spark plugs would be a good place to start .. then replace the ignition wires, clean the coil insulator .. clean or replace the distributor cap .. when you replaced the O2 sensor that should have eliminated the "heater circuit" problem (the O2 sensor has a built in heater that gets it up to working temprature faster at warm up) .. .. if the wiring and connectors to the O2 sensor are ok then that fault code should go away .. multiple misfires will keep the trouble light on .. that could also be caused by a sticking or dirty injector or dirty throttle body.. you can use a good injector cleaner for that .also look for a cracked vacuum hose ... it would be good to know the present fault code since it should have changed once you installed the new O2 sensor .. there may be two O2 sensors (one later in the exhaust system) ..it sounds like you got the right one but make sure ..it may take some time for the computer to adjust to the new O2 sensor and for the injector cleaner to work .. make sure new plugs are gapped properly and use an "antiseize" compound on the threads .. that reduces the probability of the plugs sticking in their sockets .. on aluminum heads the plugs want to seize (or weld) in place after a long time. .. that makes them really hard to get out later .. just a tiny amount of antiseize compound on the theads helps a lot .. be careful not to overrtighten plugs in aluminum heads ..
if your engine is badly missing on one cylinder (you should easily detect that) then a sticking injector would be suspect .. there are some simple ways to get it working again if thats the case ..

SOURCE: i have been losing coolant but its not on the

Your coolant may be going somewhere else.
You may have a head gasket issue...
Pull the oil dipstick to see if its milky...
If so take it to a reputable mechanic and see what they find..

SOURCE: 2003 Grand Prix service engine light on even after new catalytic

I wouldn't have gotten a cat. If the o2s are all replaced, then it could be an EGR valve

SOURCE: i have a 2001 pontiac grand am se and my car wont

verify the oxigen sensors and catalityc converter

Harvey N Tawatao

• 3854 Answers
• Posted on Jun 09, 2010

SOURCE: i have 2005 pontiac grand prix the code p0420

Inspect the O2 sensor after the Catalytic converter, make sure the lead wires are good and not damaged from corrosion and heat. If all wire leads seem to be good, replace the O2 sensor and try to stay away from after market sensors. They don't last long and as for your Catalytic Converter, you can check it by bang in on it to see if there are any rattles coming form the inside.
The good news about a bad Catalytic Converter is that Gm covers them under warranty for up to 8 years.
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