Help me find vacuum leak?

[Mike1919]

As the title says i cannot for the lufe of me find a vacuum leak. I have a high idle, right between 1000-1200 and the second i turn the engine off, if i remove a vacuum line from the plenum, its already lost vacuum. I tried the starting fluid trick as well as the unlit propane torch trick. I went all around thd throttle body, all along tge intake vasket as well as the plenum with an unlit torch. I hit every connection and followed the vacuum lines down to the next connection and got nothing. I also tried the plenum gasket and got no signs of a leak. Correct me if I'm wrong but the plenum should hold vacuum after the engine is shut off right? I dont know where else to look. Also my cruise control doesn't work, but i unplugged the line from the tree and capped it off to eliminate that possibility, thanks

 

[Mike1919]

Well for anyone who was wondering it was a bad throttle body gasket.

 

[ranger1997]

Surprised that didn't show up with the starting fluid.


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[Mike1919]

Surprised that didn't show up with the starting fluid.


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Yeah i even ran a propane torch around it and it didn't pick up. Glad I found it though

 

[Mike1919]

Well it was good Saturday, i pulled codes and code 411 was gona. Now its Monday morning and it's back to a 1200 rpm idle. Kind of puts a damper on things. I called my local mechanic and they said its $120 for them to diagnose it. I'm now thinking that would be better instead of taking guesses.

 

[Mike1919]

Also id like to mention that unplugging the new idle air bypass valve while running does nothing. Nothing at all

 

[Mike1919]

Okay well i got it in the shop and tgey said someone has tampered with the throttle body and drilled a hole in the butterfly valve thats not supposed to be there. I think thats the problem

 

[Mike1919]

Well I'm going to the junkyard this weekend to get a throttle body, can i grab one off of a explorer with the 4.0? Also mine does not have an egr system. Are the throttle bodies different for the trucks with a 4.0 and egr compared to one without an egr valve. Thanks