08 F150 4.6 XLT super crew.

This afternoon I went to start my truck and right as the engine started I got a very very quick jump of RPMs and it went back to normal. the truck ran fine.

latter on in the evening I started it up again and it did the same thing but not as harsh this time.

My foot was not any place by the gas peddle and I just turn the key on and click it to the start position, and it starts right up.

 

The temps might have been cold enough to turn on the high idle. Mine will rev at around 1200 until its warmed up, then it drops down to 850 or so. I can get the exact numbers later today.

 

Original start up cold = 1400rpm
about 5 seconds later = 1300rpm
Several minutes later (150F) = 800rpm
Operating temp (180-190) = 600rpm idle

 

thanks but thr rev is only about 1- 2 seconds

 

Sounds normal to me.

 

this is what I was wondering, it hasnt done it but the two times. but then again I havent driven it on over a week

 

My truck has been doin this as well for a little while, when i first start it in the morning it revs at like 1900 for a few sonds then drops to around 1200-1400. after a little bit if i let it idle it drops back down to normal.