Bogging/almost stalling at idle - IACV?

[3.0ranger1227]

My 03 3.0 is bogging down at idle, it revs to high idle and then when it drops down it almost dies, before revving itself back up. Is this a dirty IACV? I had a friend with an expedition that did this because of a dirty/bad IACV but wasn't sure if the ranger was doing the same thing. If it is that, should I just clean it with some brake cleaner and paper towels?

 

[BlackBII]

It's very possible.

Pull it off and look. There is a plunger inside that should move freely back and forth. It can get dirty and prevent the valve from opening all the way.

Here's a good view of how it works. (Stolen from http://fordfuelinjection.com/?p=39)

 

[3.0ranger1227]

Thanks. I'll try that when I get a chance... There is not really a whole lot that can break there, right? solenoid could go bad i guess... I might just get another

 

[disciplerocks]

If you are not throwing a code, it may be the fuel pressure regulator. But most likely it is the IAC.

 

[robmedina]

check to see if your pcv valve is seated properly too. turned out mine wasn't .

 

[3.0ranger1227]

PCV? sorry for the dumb question.

Mine is not throwing a code.

 

[stevecast]

would the IACV cause the engine's idle to act erratically like he mentioned , or would it cause a missfire ... not to hijack but i have a serious miss fire and the computer reads IACV is bad. i seem to think i have another problem. any help pls thanks

 

[ShadeTreeMech]

In one of my vehicles (a Honda Accord), I experienced the problem you're having...the engin would race to about 1700 rpm then drop to idle, then race again to 1700, back to idle. It would continue this pattern until I shut it off, spending a second or so at each rpm. It eventually threw a DTC (diagnostic trouble code) which when read with my scan tool led me straight to the Idle Air Control Valve. Are you getting a DTC or a pending DTC (the latter is an indication of a problem that hasn't set the check engine light on, yet)? A little money ($75 to $100 (don't recall exactly) for a new IACV) and elbow grease (about an hour of work) later, the problem was fixed.

I'm surprised that yours wants to bog down when it idles. When you replace or clean your IACV, you might want to clean your throttle body at the same time...often problems with poor idle quality and some trouble codes are attributable to a coked-up throttle body. I worked on an Explorer for an acqaintance once than had a MAF sensor code and wouldn't idle (though it would run if you kept it revved up). After cleaning the throttle body and allowing all of the throttle body cleaner to burn out of the intake manifold, the Explorer idled like a champ and the code cleared itself.

 

[Earl43P]

In one of my vehicles (a Honda Accord), I experienced the problem you're having...the engin would race to about 1700 rpm then drop to idle, then race again to 1700, back to idle. It would continue this pattern until I shut it off, spending a second or so at each rpm. It eventually threw a DTC (diagnostic trouble code) which when read with my scan tool led me straight to the Idle Air Control Valve. Are you getting a DTC or a pending DTC (the latter is an indication of a problem that hasn't set the check engine light on, yet)? A little money ($75 to $100 (don't recall exactly) for a new IACV) and elbow grease (about an hour of work) later, the problem was fixed.

I'm surprised that yours wants to bog down when it idles. When you replace or clean your IACV, you might want to clean your throttle body at the same time...often problems with poor idle quality and some trouble codes are attributable to a coked-up throttle body. I worked on an Explorer for an acqaintance once than had a MAF sensor code and wouldn't idle (though it would run if you kept it revved up). After cleaning the throttle body and allowing all of the throttle body cleaner to burn out of the intake manifold, the Explorer idled like a champ and the code cleared itself.

Very well said, and Welcome to The Ranger Station!

 

[3.0ranger1227]

In one of my vehicles (a Honda Accord), I experienced the problem you're having...the engin would race to about 1700 rpm then drop to idle, then race again to 1700, back to idle. It would continue this pattern until I shut it off, spending a second or so at each rpm. It eventually threw a DTC (diagnostic trouble code) which when read with my scan tool led me straight to the Idle Air Control Valve. Are you getting a DTC or a pending DTC (the latter is an indication of a problem that hasn't set the check engine light on, yet)? A little money ($75 to $100 (don't recall exactly) for a new IACV) and elbow grease (about an hour of work) later, the problem was fixed.

I'm surprised that yours wants to bog down when it idles. When you replace or clean your IACV, you might want to clean your throttle body at the same time...often problems with poor idle quality and some trouble codes are attributable to a coked-up throttle body. I worked on an Explorer for an acqaintance once than had a MAF sensor code and wouldn't idle (though it would run if you kept it revved up). After cleaning the throttle body and allowing all of the throttle body cleaner to burn out of the intake manifold, the Explorer idled like a champ and the code cleared itself.

Thanks. I'm sure its the IACV now, I just need to get the time and tools to do it.

 

[Earl43P]

Don't need much.

8mm wrench or socket and some carb/choke cleaner.
I've used Deep Creep too, that's a good enough solvent.

I also hit the shaft with a .22 caliber bore brush to knock off the stubborn carbon.