As the title says iv got a idle problem with my 2006 fx4 5.4 with 103,000 miles. Background its got new plugs, gotts mod, and KNN drop in filter. Iv cleaned the throttle body twice during the life of the truck. I have also ran sea foam through it 3 times for the life of the truck. The problem - on start up the truck idles at around 800 to 1,000 rpm until it reaches operating temp, then it idles down to regular idle where it should be. Anyone know what is causing this and how to fix it? if i put it in gear it idles fine as well . Just does it in park and N until it warms up. Thanks

 

Scanned for codes? TPS maybe.

 

Or, have you tried the "throttle reset trick". Turn the key to on (but don't start), depress gas pedal slowly all the way down and back up slowly a few times. Some guys say this resets the throttle somehow.

 

Iv done that a year or two ago. Couldnt hear to give it a try.

 

All of these trucks do that. I don't know of any vehicle that immediately starts up and idles at its lowest point.

 

It shouldn't stay at 1000 RPM until it reaches operating temperature, though. At most a minute or two in very cold weather.

 

Like VTX1800 said..i don't see anything wrong with it if it idles higher rpms for a min or 2 during inclement weather.

 

Also..when you said ran seafoam 3 times..guess that was with gasoline. If you did not for the crankcase..its probably a good idea. Just before oil change add (I believe 1.5 oz per quart of oil)sea foam to eng.oil run it at idle for a good 5-7 min..and then drain. Seafoam site claims you can drive for 30min b4 you change oil. Its supposed to clear the sticky valves and residue that built up over time.

 

TPS...

 

Honestly, the symptom sounded kinda normal to me also except the higher idle should go down to normal only after a minute or so after cold start up. But I'm giving you the benefit of the doubt because you'd be the first person to notice something different about your truck. Often, I don't think that's taken seriously enough with mechanics.