Elevated idle 03 Explorer XLT

[olsem101]

Ok guys i have an interesting problem. Recently my dad purchased a 2003 explorer xlt 4.0 v6, and we have noticed some odd idle and start up issues with it. First, when started up cold it fires up to 2000rpm like normal but it drops down to 1000 rpm then does recover a bit to 1200. This sounds almost a bit normal when i type it out here, but what i am complaining about is that it isnt a smooth fire like the other 3rd gen and 4th gen that we have. They both fire up smoothly to around 1500 when cold and taper off down to 1000 or so then slow to 550-650 like they are supposed to. Now along with the odd cold start it also "skips a beat" when it is still warm and started back up. Next in this nice saga is what it does after it fires up which is that the idle fails to go below about 950-1000rpm when thoroughly warmed up. That is the real annoying part of my problem, however, now and then (and by that i mean not very often, but it can happen) it will drop down to low idle when coming up to a stop sign, but if it is put into park then it will slowly creep back up to about 950-1000 once again. Also, that elevated idle isnt the smoothest in the world either, when sitting in it when warm you can feel the motor shudder a little bit as in the classic rough idle. It runs perfect on the road though, the only problem is the idling with it. Things I have tried: I first started out by installing new plugs because the old ones had never been changed in 122,000 miles, didnt change. Cleaned IAC, no change. Replaced IAC, no change. Replaced TPS, helped some rough running around 4000 when throttle was held open but still no change with the problem at hand. Also we installed a new alternator as the old one died on us on a cold day and almost got stranded along the road, but no change. I am sick of throwing parts at it, i wonder if my problems are computer related as in it needs the newest "flash". My 04 we updated that for throttle pedal response and that really helped there. Oh i forgot to mention, this 03 has an astrostart remote starter on it too. I dont know if that affects them in any way though.
http://www.justanswer.com/ford/2dvsm-2002-ford-explorer-4-6l-engine-stall-intermitentaly.html

The link above is a TSB for the 4.0 explorers not the 4.6 like the title of the webpage it is on. Scroll down a ways to find it. Is that the TSB i should ask about maybe???

Any help would be appreciated!

 

[96eb96]

probably intake gaskets are letting in air when cold and need replacement. What are your short and long term fuel trims at idle?

 

[olsem101]

I dont know what the fuel trim is at. I may be able to get a scanner tool to check that out next weekend, if i can figure out how to work it.

 

[olsem101]

Leaky intake gaskets would be the culprit even when the engine is warmed up and idling?

 

[olsem101]

ok as promised. I just checked the fuel trim on this explorer. The short terms (both banks) are hoping on either side of zero. The long term ones are steady around -5 to -6 percent. While i was at it i also checked my 04 and the short term were the same but long term ones were 5 to 6 % above zero.