Lost 300-400 rpms on idle

[Jukelemon]

Hi all. Strangest thing. Go to work today and the truck will not idle over 350-400. Flip the AC on and it is back where it should be. I would think it should be lower-lower across the board you know.

Pop the hood and I can hear, for lack of better words, what sounds to be air/exhaust coming from somewhere around the manifold. I mean a sh-t load of air. Sounds like an air pump in cycle if you know what I mean.

So, before I make a commonsense call and say the idle issue is from a manifold leak, am I missing something?

About a year ago, when I replaced my entire exhaust (manifold back) the fellow said I had a "small" leak. Perhaps it is bigger??

If so, should I try cranking down the manifold bolts-gently? Gasket issue or do you think a crack with that much air?

And please don't say buy a header LOL!!! You all remember my comments from that post.

 

[WristPin]

a leak in he exhaust wouldnt cause the R's to drop.
Only a leak in the intake side would.
You know what you have to do. But if it just started out of the blue, a loose hose is where I would look first.
But either way, I have a nice pacesetter hedder you can have for 25 bucks shipped to your door. It will solve all your problems forever! Guaranteed!

 

[Jukelemon]

So, it is coincidence about the exhaust leak?

I knew you coudn't hold back a header comment!!

 

[liljlandon]

Maybe your exhaust leak is hiding your intake leak

Wristy clear your PMs.
Do you really have a header for 25 to my door?

 

[WristPin]

Maybe your exhaust leak is hiding your intake leak

Wristy clear your PMs.
Do you really have a header for 25 to my door?

no, i am just givin Juke a hard time.

 

[WristPin]

So, it is coincidence about the exhaust leak?

I knew you coudn't hold back a header comment!!

yeah. an exhaust leak will make it hard to hear an intake leak, but it wont cause a drop in idle.

 

[liljlandon]

no, i am just givin Juke a hard time.

DAMN!

 

[Jukelemon]

OK. So, you guys recommend spraying WHAT around the intake in order to find a leak? I can't remember.

Thanks

 

[2ndGenToyotaFan]

Napalm..... No wait.... uh propane or starting fluid....

 

[Jukelemon]

Napalm..... No wait.... uh propane or starting fluid....

LOL!!!

Thanks man.

 

[2ndGenToyotaFan]

 

[WarDamnEagle]

Carburetor cleaner works also.

 

[Jukelemon]

Problem Found!!!

Well, I found the issue.

There was a hose disconnected going from the intake to the top of the valve cover (valve cover nipple closest to the front, left valve cover bolt). I am not sure how it came off, but it did.

I found it by a tracing all of the hoses going into the intake.

Put it back on the valve cover and WHAM, an extra 400 rpms at idle ( :

Thanks all for the direction!!!!

Juke

 

[WristPin]

oh, happy joy!

now go get that thing muddy!