1998 Chevy Van Loss of horsepower

1998 CHEVROLET VAN

163,000 MILES • V8 • 2WD • AUTOMATIC

SATMAN223

MEMBER
2 POSTS

I'm experiencing a problem with a loss of horsepower. As I accelerate, I hear little "pops" coming from the engine location. Soonafter as I continue driving, I notice a gradual decrease in horsepower. The transmission seems to shift a little rough shortly before this happens. As I drive, I will actually lose enough horsepower to make the vehicle slow down to the point where I have to take my foot off the throttle to regain horsepower. Once I have done this, with a little pressure I may gradually increase but the overall loss is still there.

Feb 18, 2008 at 4:57 PM

BLACKOP555

✓ASE Certified Mechanic
10,386 POSTS

I would like you to check for a exhaust block.

warm the vehicle then turn it off and hook up a vaccum guage and then fire it right back up. then incrase idle to 2,000 rpm and keep it steady while watching the vaccum guage, if pressure slowly goes down or you have to give the vehicle more gas to keep it at 2,000 rpm you have a restriction in the exhaust system. alternate way to test this is to warm the vehicle.

turn it off hook up the guage fire it up and then hit the pedal right to the floor, if the pressure drops really low then slowly goes up you have a restriction also.

Feb 18, 2008 at 6:32 PM

SATMAN223

MEMBER
2 POSTS

I already replaced the Mass Air Flow Sensor and that seemed to help a little. It added more horsepower upon start up...however, after a while, the vehicle seems to become "bottled up" and it almost feels like you have a "banana in the tailpipe". I'll have my mechanic run your diagnositic.

[quote:f28b1ddbe9="blackop555"]I would like you to check for a exhaust block.

warm the vehicle then turn it off and hook up a vaccum guage and then fire it right back up. then incrase idle to 2,000 rpm and keep it steady while watching the vaccum guage, if pressure slowly goes down or you have to give the vehicle more gas to keep it at 2,000 rpm you have a restriction in the exhaust system. alternate way to test this is to warm the vehicle.

turn it off hook up the guage fire it up and then hit the pedal right to the floor, if the pressure drops really low then slowly goes up you have a restriction also.[/quote:f28b1ddbe9]

Feb 18, 2008 at 7:03 PM

Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.