Hiss I have never heard before.

[Abraxsis]

Yesterday I cleaned out my IAC because I was getting the usual "chug chug almost dies" symptom upon starting and putting the truck into gear. But when I was finished I was manually reving the engine from under the hood and everytime I did I heard a quick but loud Hiss sound the second I moved the throttle arm. It sounded like it was coming from top center of the engine, but seeing I havent rev'd my engine with my head under the hood alot I dont know if this Hiss is normal. Anyone?? My 01 Sport has 80k on it, could it be the intake manifold O rings that I have heard about?

Abraxsis

 

[spindlecone]

Get some carb cleaner and spray it around the areas you suspect, if the engine stumbles, you have a vac leak, good luck

 

[ExplorerDMB]

you can try that. You didn't have your intake hose off did you? The Throttle/Butterfly will make that noise.

-Drew

 

[gijoecam]

you can try that. You didn't have your intake hose off did you? The Throttle/Butterfly will make that noise.

-Drew

Ditto. A his when you crack the throttle is normal. It's the air rushing through the throttle body. Perfectly normal.

-Joe