I HAVE A 99 F-150/4.6L ON START-UP, HOT OR COLD, ENGINE RPM REACHES 2000 RPM AND THEN IMMEDIATELY DROPS BACK TO NORMAL. IS THIS HIGH? I'VE BEEN IN OTHER F-150'S THAT DO THIS, BUT THE MAJORITY REACH ABOUT 1500 RPM, THEN DROP BACK. DO I NEED TO HAVE IT LOOKED AT?

 

I would say that as long as it goes to a decent idle of like 1000 in park and something like 750 in gear, and it idles smooth, dont worry about it.

Some days ,y truck will jump up to like 1800, sometimes it will goto 1200, it just depends, I have no idea what actually makes it do this,

 

My 99 4.6 does the same thing. I find it anoying but I am not to worried about it

 

My 2000 5.4 does the same thing as does every other i have heard. I did not like that at first but don't pay it much attention now.