1998 Buick Century Buick Century Heistation

SKARICAVISION

MEMBER
1998 BUICK CENTURY

Engine Performance problem
1998 Buick Century 6 cyl Front Wheel Drive Automatic 120K miles

1998 Buick Century, 3.1L V6, 4t60E tranny, 120K miles.

very sluggish acceleration and hesitation in all gears only once warmed up - especially on light acceleration - no problem when cold - engine runs fine in park or neutral warm or cold - no vaccuum leaks have been found. Also, terrible gas mileage now - no OBD-II codes

changed TPS as it was in bad mecahnical shape when removed - no improvement - removed and cleaned MAF sensor - no improvement - driving with unplugged MAF sensor makes it run fine (except for CES light of course) - should I replace MAF or I am just masking the root cause by unplugging MAF?

3 Replies

JERRYGOODWRENCH

MECHANIC
77 POSTS

You might want to check the timing chain whih will make it run fine when it's cold and then when it warms up the timing chain stretches and you will have a loss of power especially going up hills. Also have you checked the convertor. If plugged this will cause the same thing. Let me know. Jerrygoodwrench.

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Saturday, April 18th, 2009 AT 6:55 AM

SKARICAVISION

MEMBER
2 POSTS

Thanks Jerry.

Checked the input and output temperatures of the catalytic converter - much hotter leaving the cat than entering so all seems to be good.

Changed the MAF and EGR sensors with parts from the boneyard - MAF made no difference but EGR that came off had a pintle that could be pushed in and out with just me blowing on it. Pintle on replacement EGR was solid and could not be pushed in (btw, digital/linear EGR on this motor) without being connected to motor. Much better now. Will keep you posted if the problem returns.

Could a fualty EGR cause this problem?

Txs

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Monday, April 20th, 2009 AT 10:38 AM

JERRYGOODWRENCH