02 GranPrix GT 3.8 108k miles. engine won't rev past 3k

2002 ALL OTHER MAKES ALL OTHER MODELS
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K4ITF
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My 02 Grand Prix has issues. It starts and idles fine, runs perfect up to 2200 or so RPM , At full throttle the engine wont run past about 3500 rpm. no load. when driving, usable power is limited to about 2200 rpm and below. transmission shifts fine and on flat ground it can be driven to highway speeds but will only pull up a hill about 20 mph since if you let it downshift you dont have the revs to back it up. I replaced the fuel filter, and checked the fuel pressure on the rail @ 50 psi even while at WOT hovering around 3000 rpm. I have also checked the EGR valve, it was clean and moved freely. ECM shows no codes stored and no check engine light comes on. Anyone got any suggestions?
Feb 22, 2007 at 6:52 AM
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KNIGHTRIDERKITT2000
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try having it checked for a plugged catalytic converter, that would be my guess
Feb 25, 2007 at 9:51 PM
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K4ITF
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What would be the proper way to test for this problem? Can I measure the exaust back pressure by taking out the O2 sensor before the Cat and measuring there? If so, what would be the normal reading?
Mar 1, 2007 at 2:50 PM
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K4ITF
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Problem solved. Converter was plugged tight. I removed the front o2 sensor to check the rev and car ran fine. I ordered a new converter and had it installed today, and it runs perfectly again. Thanks knightriderkitt2000, you were right on the money. :D
Mar 14, 2007 at 9:21 AM
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