When I start my 2004 FX4 F-150, after it has sat for a couple hours, sometimes right after the starter has turned the engine it revs really high for about half a second and then resumes regular rpms. This doesn't happen all the time and not in any particular temperature, and only right after the engine starts. Is this normal? Has anyone else experienced this? Oh yeah, I have a 5.4L Auto.

Thanks

 

My 5.4L goes into race mode almost anytime it's started, hot or cold. I usually have to wait about 15 seconds before putting it into gear. I'll check the RPM next time, but it's above 1500. Dealer says it's normal, but I don't think so.

 

I think the dealer is right, all the new cars and trucks are set up like that, but check with your Dealer,ask them to run an Oasais (sp) or check for any recalls, ask them to show you any other truck like yours to see if it acts the same.

 

normal-depending what "really high" means.

 

mine will idle higher for a few seconds right after startup, then drop to normal idle rpm. my two rangers (01, 03) prior to my 04 f150 fx4 did this as well, was told by my dealer that this is a warm up function for the engine, reguardless of a cold or warm start.

 

Correct. If you dont like it you can get your gas pedal and give it a "quick" stomp and it will idle down. FYI.

-Matt

 

"Really high" means around 2000 rpms. Again it only does this for approx. a half second right after it starts. It is very random, but does not seem normal. I think I will keep an eye on it and then take it to the dealer if it continues. Thanks

 

I've tried to figure this out beforre and ended up getting many different answers. Some say it's to warm-up/ get oil pressure sooner, some say it's emmisions, and some say it's part of the start-up diagnoses. I've even heard a few I don't remember. It won't happen all the time as it's from the computer and only certain parameters call for it (I can't figure them out though). I wouldn't waste time at the dealer unless it needs to go anyway. Go if it will make you feel better, but it is normal.