Fast Idle on Cold Start

[Whimsey]

My 2002 F-150 and the Wife's 2005 Exploder, both with the 4.6 V-8 make that "roar" shortly after starting for a brief period. I think it has to do with the emission control system. Otherwise we don't hear any "roar".

Whimsey

 

[Warlord]

I should point out that my truck is a 2.3 duratec. It roars at start up and then 10 seconds after you can hear the fan turn off. I think these trucks have an e-fan and a clutch fan so I guess my truck acts the same way yours does Whimsey. I started up my dads blazer today and it only ever hit 1200rpm. That was what worried me but it seems I have nothing to worry about.

 

[road_rascal]

OK- I made a note of this when I cold started both of my Fords: the van will idle around 1300rpms for about 30secs then back down, the Taurus (24v) will idle around 1800rpms for around 30secs and lower to around 1100 for about 10secs, then idle normally. I can get both to kick down quicker by blipping the gas lightly.

 

[CBDFrontier06]

Both my Frontier and Sport Trac seem to have locked radiator fans on cold mornings...they roar, then it slowly fades away as the fans slow down. Doesn't make much sense that a heat-actuated clutch locks when it's 30 degrees outside, but they aren't the first trucks I've heard do it.

I, like others, cringe when my Frontier rockets to 2000 rpms at startup. The Sport Trac isn't as extreme in this manner, and actually only makes it to around 1500...and it's not always a quick snap like the Frontier.

 

[TheLoneRanger]

My 2000 Explorer ran up to 1800 rpm when starting, and was getting on my last nerve. After trying everything to lower the idle short of a PCM re-program, I finally hit upon the idea of restricting the airflow through the IAC. I cut a short section of 5/16" fuel hose and pushed it into the inlet side of the IAC. This dropped the start-up idle down to about 1400 rpm, which sounds much better to me. This was about 50K miles ago, and no problems from it so far......