Mechanics

MY TRUCK MAKES A SHHHH SOUND WHEN I ACCELERATE THE AIR PEDAL.?

1995 Chevrolet S-10 • 64,000 miles

I had my catalytic converter checked that's not it, plus my truck jerks if I accelerate to fast also I can press the air pedal all the way down and it wont speed up at all, I checked my transmission, it switch gears my belt is good. So, over all I hear the "sHHHHH" sound only when I accelerate the air pedal, and when I accelerate fast from stop position it wont move fast it will climb RPMS slow.
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Jojos10
October 7, 2012.



Sounds like the cat converter is clogged. Have the back pressure checked to verify

Roy

Did you check for trouble codes? Is the Malfunction Indicator Light showing?
Noise described seems to indicate a leak somewhere or clogging in exhaust system.

KHLow2008
Oct 7, 2012.
Roy yes it was checked, also, no cel comes on.

Tiny
Jojos10
Oct 7, 2012.
How was it checked? What was the back pressure measurement?

Roy

I saw him put his hand over tail pipe.

Tiny
Jojos10
Oct 7, 2012.
Thats not a test. It can still pass enough exhaust to feel it but not let the engine breathe.

Thats why you need to measure the back pressure.

Roy

@ Roy I just had my cat converter installed a month ago my engine is good, it never blow black smoke out the tail pipe also, thank you for taking the time to help me with this problem.

Tiny
Jojos10
Oct 8, 2012.
Sounds like a gross vacuum leak actually, something intake side or brake booster. Those are the biggest lines you have in the system ( 1/4 ) some larger. Especially if its leaking to the booster that will cause a whole host of issues. If vacuum is dropping in the system it also could be shutting down the fuel pressure regulator which would allow more fuel into the rail under hard acceleration.

Evolve960
Oct 10, 2012.
I found out it is the EXHAUST manifold flange gasket. May I ask will this cause all these symptoms?

Tiny
Jojos10
Oct 10, 2012.
Yes, exhaust leaks can cause performance related issues. Have it rectified first.

KHLow2008
Oct 10, 2012.
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