I own a 2005 F-150 STX that got out of the shop last week. The A/C compressor was leaking and I had to have a new compressor and drier installed. A week later, the CEL suddenly comes on while I'm driving. I checked the fuel cap for tightness and a quick inspection under the hood showed no obvious leaks. Is this a known issue to anyone else?

 

so you didn't bother having the truck checked for codes??? but you did check the fuel filler cap, good for you, now go get teh codes checked before you do some damage, because something tells me you're still driving the truck

 

Just wen to autozone and had the codes checked (they do it for free). The guy said the problem is an unusually high idle RPM. This can cause erratic idling and misfires. He said it could be a dirty throttle body or leaking vaccum hoses. Fortunately, he says it shouldnt hurt the truck to drive it around.

 

NEVER listen to those guys. So what was the code ? Their scanner spits out a DTC, -that's what you need to get. You have to post the code or no one can help with this.

You posting in the wrong forum anyway, -I doubt you'll receive much help.

 

First, wrong forum, as stated.

Second, we don't know what you're driving other than it's an 05 F150 STX.

Please add your truck's info so we can get this moved to the proper engine forum and get you hooked up with an answer.

 

truck specs
gasoline 5.3l v8 automatic

the error code is p0506

 

You have a Chevy engine?

Your throttle position sensor or electronic throttle body itself is on the way out. I'd pull the throttle body and clean it.

 

Actually P0506 - IAC system RPM lower then expected

Possible causes:
Air Intake Restriction
Exhaust Restriction
Engine Mechanical Fault
Sludged Throttle body
Damaged Throttle body
Damaged PCM

My guess would be your Idle air control motor is failing or you just need a throttle body cleaning. Also clean your MAF while you are at it and disconnect the battery for a while to let the truck relearn.. Sorry I cant go any futher at the moment I'm already late to go to my dads lol

 

The 05 doesn't have an IAC, it has a full electronic throttle. The IAC code with an electronic throttle indicates a problem somewhere in the throttle system, either mechanical or electrical.

 

did the guys at autozone tell you your engine size as well???

 

dang I knew I entered something wrong. No its a 5.4 liter engine. From what I read online, cleaning the throttle body is a dirty and potentially risky job due to the amount of hoses and wires you have to disconnect. Is this a little weekend job I can do myself, or should I have a garage do it?

 

If your eyes aren't crossed and you don't drool on yourself you SHOULD be able to do it. It's not THAT hard a job, unless you are not used to doing mechanical work, then I'd take it to a professional. If you do it, get the throttle body cleaner, not carb cleaner. Too many people listen to advice from 20 years ago!

 

I think that's what he was saying when he said "idle air control MOTOR". May be done electronically (slave motor command) but it's still controlling the amount of air that comes in to produce a proper idle.

 

Brew- ever notice those guys eyes are kinda crossed and glazed over??? Maybe they were holding the print out upside down when they read it.