Ditto. You might have a minor leak there, but if it's not real big then the idle-air-controller can compensate. Looks like your throttle-body could use some cleaning.

 

Thanks everyone. This vacuum leak I've been chasing down is significant enough to mess up the heater vents again and cause rough idling and it seems to be running lean and guzzling gas a little more than usual.

But I will do the carb cleaner check today thanks.

already ordered a bbk throttle body for 300. Hope this is it.

 

You've checked the lines and the vac reservoir behind the bumper?

 

Yes, too many times. Tried the brake cleaner trick. Tried the unlit propane trick. Nothing. But i wasnt spraying random metal engine parts. I was following the vacuum lines.

Finally i resorted to that wacky cheap cigar/hand pump smoke test. The only place i saw any smoke coming out was the throttle body shaft and the airbox.

 

yeah i went over that spot with unlit propane today and no change in the idle. My heart sank. Thought i had finally found this effing vacuum leak! Might as well return the new throttle body. And now i need to start another vacuum leak thread. Ugh

 

One last question if i can squeak it in… The new throttle body from bbk ended up being a gift so it’s free to me. Is it worth putting in the jeep anyway, even if it’s not the source of the vacuum leak?

In the marketing it claims to increase hp or power or something a little.

If it won’t be a decent upgrade I’d rather be nice and get the wife a refund. Thanks

 

Be nice

 

Have you actually measured the vacuum? I almost feel like you're chasing a different problem, and low vacuum is a symptom not a cause.

 

You are correct! I actually have no bleepin idea whats wrong with it. Seems like another vacuum leak with the heater stuck on defrost and the rough idle. But who knows. Ol’ Jeepjeep is 30 years old now.

I realize that this thread is done and I should start a new one if i have other questions. But what are my questions? Anyone know what i should look at next? Or maybe it’s time to have a pro look at it?
But, the wife just innocently took it to a mechanic for the brakes recently and they took advantage of her and we paid about triple what the job was worth.

How can we even find an honest jeep mechanic? Sigh. Yeah thread probably isn’t the place to ask that.

Anyone at least know what I could try next? Another smoke test maybe? This time use more cigars and ignore the throttle body?

 

This thread has gotten pretty long so I might have missed it but it's not clear why you think you even have a vacuum leak, as opposed to who knows what causing rough idle a maybe poor gas mileage.
it might help the internet diagnostics if you:
Listed the symptoms.
Listed what maintenance you've done recently ( parts replacement, tune up, etcDid the symptoms start suddenly?
I think this might be a case of "target fixation" re the vacuum leak

 

Okay. It sat unused for a couple years besides the occasional short drive. The heat was out, so I replaced the blower motor and some kind of resistor or something, a cheap part that had fried when the blower motor quit. I cleaned out the a/c vents and all in there the best i could with some scrubbing bubbles.
I put in an new thermostat and changed the coolant. Changed the oil.

The heater vents are stuck on defrost so I figured like in the past it was another vacuum leak. Put on a new CCV and started hunting.

That’s where i am now. The smoke test only showed smoke around the throttle body shaft area, not even the gasket area, though the TB was loose before I tightened it to 9ft lbs.

 

Vehicles hate to sit; rust, mice,old fuel, rotten rubber.
​​​​​​Earlier in this thread you mentioned poor idle and fuel economy. If it were mine, which it's not, I would somehow get all the old fuel out of it, then replace the fuel filter, replace the plugs, plug and coil wires, rotor and cap, air filter , and other routine maintenance stuff I may have forgotten.

Look at the wiring for mouse chews. Clean all the grounds.

As far as the " stuck" HVAC it sounds like you have checked for leaks, is the HVAC stuff actually getting vacuum? It may just be stuck, or maybe a mouse nest.

Keep in mind that the thing is 30 years old+sat for a while.

 

 

Note that blowing smoke into the intake will not show if you have a leak beyond that check-valve.

 

Look at Cruiser's diagram. Check the line marked "To Heater AC Controls" where it goes through the firewall. It's small and hidden behind some wiring and other crap. Mine was frayed at the connection there and leaking, although it appeared o.k. at first look. I had enough slack and cut the frayed end off and re-connected it. Idle smoothed out and heater controls started working again.