Hi there.

I have a 95 f150 with a 5.8 351w. 213k miles.
I've had an odd problem that has happened since I got the truck, but I never figured out what it could be.

When I start the truck, it fires right up with no hesitation and idles at about 700 for a few seconds. The idle then stoops extremely low and sounds aggressively cammed for a couple seconds, then shoots way up high to 1500 for a couple seconds. After that short mayhem, everything is 100% ok, and it stabilizes at 700 again. It seems it only happens if it's been sitting overnight. Because if you shut it off and start it again right after it does that, it won't do it again.

I'm not extremely concerned about this, I'm just wondering what on earth it could be. Any ideas are greatly appreciated. Thanks!