Nevada Mike

Hello F150 folks

One of my family members has a 1999 F150 in the Phoenix area with 150K miles. The few times it is exposed to cold weather it has a rough idle and almost dies. By cold I mean Arizona cold in the 50 degree range. The truck is not giving him any other problem or error codes according to him and his local shop. He is not mechanical at all so I don't really trust that but there are no dash lights. Kinda weird but I would like to give him a box full of possible parts and I will install them for him as a Christmas gift.

Would anyone mind sharing possible causes. I am very mechanical with regards to wrenching I am just not well versed on the 5.4 F150. I have done a search but there are thousands of articles and forms that come up. I am hopeful someone will give a shotgun approach to the top 5 or whatever is appropriate and I will just fly down and change them all out at once.

Thanks for any help and Merry Christmas!

F150Torqued

@Nevada Mike Your Christmas Gift idea is a very thoughtful one. But it would be such a shot in the dark based on all the unknown parameters and COULD involve any one or more of many parts. How about opting for a OBDII Code Reader / Scanner and help him narrow those unknown issues down NOW and in the future as well? Code readers are almost a must have tool now days to read and clear codes. And there are a number of inexpensive ones, and some will connect to an inexpensive APP for your Smart phone via a Bluetooth connector or a WIFI connector in the $10 to $30 range.


If you so decide, try to get one that can read "live data" and Mode 06 test results and custom Ford PIDs (parameter IDs). Some better ones can graph and/or log sensor data and upload screenshots and log files to your desktop computer. I use the Torque Pro App for Android ($4.95) with a Bluetooth interface. It will do ALL that, and am very pleased with it. But it won't work on an Iphone. There is a WIFI dongle and an Apple App for the Iphone, but I'm not very familiar with that.


Just a thought. I wish you and your fellow Ford family member a very Merry Christmas - and a problem fixed New Year.

Nevada Mike

@Torqued thanks for the reply. He is totally non mechanical and would probably never use the OBD.

I may just start with the IAC and see what happens

F150Torqued

I understand. With that in mind and revisiting your OP, the IAC is a reasonable place to start. Consider also the EGR valve (or maybe cleaning instead of replacing depending on the budget). And the intake air temperature sensor because it plays a part in operation of the EGR which is a typical culprit of rough idle / stalling. You mentioned the problem is worse in cold weather.


It is a thoughtful Christmas gift. Hope everything works out.

1917-1911M

How about a new set of spark plugs. $8 or so each. As others have said...too many things could be causing the rough idle. Can of SeaFoam to run through the engine. $10 or $12. Tune up gift certificate....$cash for a trip to get the engine tuned.

plugs
coils
EGR valve
Wiring
Seafoam
$ for diagnostic trip to dealer

The computer controls a lot of things and it depends on sensor input. Case of good beer, then you two could kick the tires as you cuss it? Good luck. M1911