2002 Buick Century, lacks power, poor gas mileage.

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goatman
Posts: 6
Joined: Sun Oct 13, 2013 10:14 am

2002 Buick Century, lacks power, poor gas mileage.

Unread post by goatman » Sun Oct 13, 2013 10:45 am

2002 Buick Century 3.1, 150,000 miles. Had EGR codes P0401 + P0404 back in July, but car run fine + had power. Replaced EGR valve back then. Codes are back on + car lacks power, no get up+go. Pulled throttle body + cleaned out EGR port, Was clogged. Cleared codes. Checked fuel pressure. 52lbs with key on,engine off. Cars still lacks power, eats fuel. Could catalytic converter be clogged + causing this? How do I check it? What else do I check. Did tune up about a year ago.


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TerryAuto
Posts: 318
Joined: Fri Dec 11, 2009 8:48 pm

Re: 2002 Buick Century, lacks power, poor gas mileage.

Unread post by TerryAuto » Sun Oct 13, 2013 9:24 pm

Yes, you could have a plugged catalytic converter. They can also set EGR codes. The proper test is to use a back pressure gauge in the oxygen sensor port. But, you can unbolt the exhaust at the rear manifold from under the car, ahead of the converter then see if power and acceleration is restored.

You could also have a faulty MAF sensor. You would need to look at airflow readings of MAF to see if they increase as RPM increases. You can also unplug it when it is running, if it dies- restart it, then see if power is back to normal.

I would also check the fuel pressure regulator. If it was leaking, that would cause the very bad gas mileage, and could be the cause of a plugged catalytic converter.

goatman
Posts: 6
Joined: Sun Oct 13, 2013 10:14 am

Re: 2002 Buick Century, lacks power, poor gas mileage.

Unread post by goatman » Fri Oct 18, 2013 7:58 pm

Will be disconnecting cat tomorrow to see if that helps. Thanks.

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TerryAuto
Posts: 318
Joined: Fri Dec 11, 2009 8:48 pm

Re: 2002 Buick Century, lacks power, poor gas mileage.

Unread post by TerryAuto » Tue Oct 29, 2013 4:32 pm

goatman wrote:Will be disconnecting cat tomorrow to see if that helps. Thanks.
Please let us know what you find.

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