2001 Grand Prix Lack Of Power


Old 10-08-10, 10:56 AM
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Join Date: Aug 2006
Location: USA
Posts: 3
2001 Grand Prix Lack Of Power

Have a 2001 Grand Prix GT with a 3800 V6-No power underload. Have replaced fuel filter, plugs, plug wires, and unhooked exhaust but still no difference. Fuel pressure is 50 lbs, vacuum is 18. Have checked coils and electronic under coil packs and all checked good. Checked resistance in injectors-13.5 to 13.7 ohms. Does not throw any codes when hooked up to computer. Any suggestions what to try next? Thanks for any input I can get!
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Old 10-08-10, 12:15 PM
Join Date: Mar 2009
Location: Texas
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You mentioned you unhooked the exhaust. Were you trying to confirm any issues around the cat converter by doing this? How many miles on the car?
Old 10-08-10, 12:33 PM
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Join Date: Aug 2006
Location: USA
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2001 Grand Prix Lack of Power

Yes I was trying to eliminate the cat. The car has 145,000 miles on it.
Old 10-08-10, 01:53 PM
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Apply the TSB below. If the condition doesn't clear post the results of a compression and cylinder leak down test.

Old 10-08-10, 05:19 PM
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Is it always no power? You say under load. Explain exactly. Like - Do you idle your way out the driveway with the engine like normal, and step on it a little to go down the street and it appears normal?, but then when you give it gas to really get going, like at stop and go light, up a hill, etc., it just doesn't have it? How does the engine sound, at idle or low throttle? - good?

You don't have rolling resistance do you?, like locked up brakes? Wheels don't get hot?

Have you tried a timing light test to see if it retarded/timing belt jumped a tooth toward the retarded side? Not sure what vacuum would be with off one tooth.

Something might be affecting the the size and hotness of the spark under load.

Maybe, for some unknown reason with the fuelpump, sock, tank debris or whatever, static pressure is good, but during dynamic, the volume falls off. Maybe you need to hook up pressure gauge to read in cabin when under load?

Maybe your fuel tank is pulling a vacuum the longer the car runs, due to some venting issue and issues with cannisters or something.

Maybe someone put sugar in your tank and it is turning to candy on your pick up screen, starving it out.

Could a stuck EGR valve cause such a thing? (But maybe that would set a code).

Faulty TPS? (throttle position sensor).

Something jammed in the fresh air intake to the throttle body?

The hardened layer of the camshaft wore off and you have severe camlobe wear now.

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