1998 Chevy Van Loss of horsepower

SATMAN223

MEMBER
1998 CHEVROLET VAN
V8
2WD
AUTOMATIC
163,000 MILES

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.

2 Replies

BLACKOP555

MECHANIC
10,371 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.