2005 Jeep GC 3.7L has unexpected high idle

[tnt_motorsports]

Well folks my son said the 2005 Jeep is making a clunk sound, so I pull it in the garage tonight to take a look. I put it up on the ramps, and climb under and notice the exhaust ground strap hanging. I touched it and moved it out of my way after a hmmmm that's odd kind of moment. I check the front driveshaft and there seems to be some play but not an excessive amount. It makes a clunking sound after the vehicle has been driven for about 5 miles when turning to the right only. The front CV joints don't click so I'm not exactly sure what this noise is. Anyway I'll monitor that situation and now to the new problem...

I start the Jeep to pull it down off the ramps. The idle immediately races to 1,500 - 2,000 RPM's and I'm like WTH!?!? It stayed between 1,500 and 2,000 RPM and would not drop. If I put it in gear it would go down to 1,000 RPM. So I shut it off and pop the hood. I noticed the CAI I out on several years ago has a crack in the plastic tubes. It is after all about 13 years old... Anyway I figure well that can't be good, so I take off the broken plastic pipe and put the air filter back on. I go to start the engine and there was no change in the idle speed, still about 2,000 RPM. I have checked all the vacuum lines, PCV lines and such under the hood and don't see any that are disconnected, loose or broken. I'm wondering if touching the ground strap has confused the vehicle some how to think it is cold and running a faster idle. I will take the idle control valve out of the throttle body tomorrow after work to see if it has a piece shrapnel in it from the CAI tube, but I'm just wondering if anyone else has ideas on what would cause this idle to go this high unexpectedly. I will probably fix the ground strap while I'm at it if anyone has a good hack for that.

Thanks in advance.
Todd

 

[Nick1994]

Probably a bad throttle body sensor or a vacuum leak.

I have a kinked cruise control cable on my Jeep that gives me high idle when I connect it. Do you have a mechanical throttle body or is it electronic?

 

[tnt_motorsports]

it's a mechanical linkage. I looked around under the hood and don't see any hoses that would cause a vacuum leak. Anyway I'll look again tonight after work.

Thanks for the tip!

 

[tnt_motorsports]

Well, fixed the ground, no noticeable difference. So I pulled the IAC sensor on the throttle body and found this nice little surprise... Part of the bloody plastic intake tube that broke. All fixed now. Thanks for the help!

 

[zrxkawboy]

Good work, and thanks for the update.

 

[incognito_2u]

Yeah......that IAC is pretty gunked up, also.......nice find with the debris from the intake tube. My 3.7 routinely gets it’s IAC cleaned and it’s O-ring Lubed with a small amount of Silicone grease. Somewhat of a common problem with these V6’s.
How many miles are on the GC?

 

[tnt_motorsports]

yeah I ended up cleaning the IAC with some gas out of the lawnmower can and a little brake cleaner. I lubed the O-ring with oil before I reinstalled it. It has just over 165,000. The body is getting soft around the rocker panels and the fenders but the power train is still good.

It has the CAI on it because the oil would foam (especially in the winter) with the factory air intake. Ever since I installed the CAI, it stopped.