"ssss" noise by firewall- drivers' side under hood
Does the noise change with speed? change with engine rpm? when braking?
is the brake petal "squishy"
I suspect a vacuum leak. Check for loose or damaged vacuum lines.
anyways does it make the noise just sitting still with the engine running and the vehicle not moving?
Looking for a Used Jimmy in your area?
CarGurus has 197 nationwide Jimmy listings starting at $2,495.
Search GMC Jimmy Questions
GMC Jimmy Experts
Related Models For Sale