Inherited from a family member, only 24,000 miles, never sat for real long periods, just not driven much. Problem: runs and drives like new, except at idle. While sitting at lights etc, the engine skips a beat, almost like a misfire or interruption, and is getting worse. It's not a constant skip either, its intermittent, and several times almost died. It has also been accompanied at times with a foul smell. Cat converter maybe? Jeez, I looked underneath and it looks like it has 3 of them on there, all covered with stainless plates and covers, looks too complicated for me. No lights on dash, scan anyway? Will one of those testers like OBDII do any good? Ford Dealer$hip? Computer Diagnostic?
Thanks for any guidance you can offer.

 

Likely an idle air control motor. They get goofy at times, especially after sitting, and rarely, if ever, set any codes.

 

...Welcome BRJ, to Ford Truck Enthusiasts!

See you on the boards. ….

 

Much thanks to MazdaRangerGuy. I believe you are correct on the idle air control... but when I went to my local parts guy, he asked if I wanted the IAC valve, or the IAC motor? Is there a difference?

 

I think you need the Intake Air Control Valve, which has the motor inside. Didn't know they sell only the motor.

 

Well thanks for the info and replies. A Ford dealership said the valve and motor are the same thing... but it is technically a valve. I bought one for $52.00 and swapped it out, but it had no affect on my problem. I still have an intermittent "shudder" at idle. While sitting at lights etc... if I raise the rpm just a little, and hold it there, it does not shudder.

Anyone have any new ideas???

 

Check the MAF and make sure the sensor element(looks like a light bulb filiment) is clean and free of debris.You can clean it with choke &carb cleaner and dry it with some compressed air

 

But whatever you do, don't touch the MAF element. It's extremely fragile. Just blow a whiff of cleaner over it and dry lightly with compressed air.

 

maybe a vacuum hose leak??

 

When I had my vac leaks the RPM's went up, not down so I don't think it's that.
Looking over this whole thread again, and noticing the mention of an odor, is this like a "rotten egg" type sulfur odor? I remember talking to a buddy about this many years ago with reference to a brand new Ford.
He worked at the dealership and said it could sometimes be caused by a rich fuel condition and that was sometimes why people smelled it only on startup from cold. Scanned the DTCs and sure enough I had a faulty O2 sensor causing a rich mixture. This was fixed under warranty but not till I had to argue until I was blue in the face with the service manager. |He was adamant that it was the brand of gas I was using which was odd since as I own a trucking company I have a fuel card that allows me to buy fuel from a bunch of different companies. I usually buy wherever's cheapest that month according to their pricing schedules.

So getting a scan is definitely worthwhile. I think that's the next logical step.
Don't go to the dealership, get it done free at autozone and whatever you do, take NO NOTICE of their diagnosis, it usually sucks and many people have come here for a correct diagnosis after buying parts that didn't fix the problem after the tech's diagnosis. Just write down the codes and come back here for a proper diagnosis. Then you can go back to the shop that kindly did the scan for free and buy whatever it is you need to fix it or do whatever you need to do to repay their good karma.