1998 Dodge Ram HISSING NOISE

1998 DODGE RAM
114,523 MILES • V8 • 4WD • AUTOMATIC
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GMAN98
  • MEMBER
  • 2 POSTS
MY TRUCK MAKES A STRANGE HISSING NOISE WHEN YOU FIRST STEP ON THE GAS. AS IT COMES BACK TO IDLE ABOUT 1000 -RPM IT STOPS LIKE AN AIR LEAK SHUTS OFF. IVE RESEARCHED ON LINE.
AND FOUND IT COULD BE THE PURGE SOLENOID FOR THE EMISSION STUFF. SOMTHING ABOUT IT NOT BEING IN THE RUBBER GROMET AND BRAKET PROPERLY AND SHORTING OUT.? I COULD NOT FIND IT. BUT I WILL LOOK AGAIN. ALSO WHEN YOUR GOING DOWN THE HIGHWAY AND STEP ON THE GAS THE AIR COND. SWITCHS FROM DASH TO DEFROST THEN WILL RETURN, IS THERE A COMMON VACUUM LEAK SOMWHERE THAT HAPPENS TO THESE TRUCKS WHEN THEY GET OLDER.?? I READ A BUNCH OF POSTS ON SOME OTHER SITE WHERE OTHER PEOPLE HAD THE SAME PROBLEM..
THANKS GARY
Jul 15, 2009 at 7:25 PM
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MHPAUTOS
  • CAR REPAIR CONTRIBUTOR
  • 31,937 POSTS
Hi there,

I feel that the hiss nd the vent problem are one in the same, you may have a vacuum leak at the manifold, (hissing noise) and when you drive and accelerate you loose manifold vacuum, if you have a leak there is no reserve to hold the vent doors in there correct position so they close off, and re set when vacuum is restored (idle &low throttle ) so check out all the vacuum hoses for a split or broken hose, start here.

mark (mhpautos)
Jul 15, 2009 at 8:34 PM
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