1992 Ford Explorer losing speed while driving

[khrysteen]

Good day everyone. I'm new to this site but thought you might be able to help me.

I have a 1992 Ford Explorer. It's 4x4 doesn't work anymore. That doesn't bother me, but I thought it might matter in this case.

When I drive the truck on the highway and get it going about 55 mpg, after a little while, it MAY, if it decides to, drop it's speed down to 40 mpg. It doesn't stall out, it doesn't do anything but slow down without me doing anything to it.

Also, in the morning, I start the truck. It usually take a few tries before it stays in idle. I have to let it run for like 5-10 minutes. If I do this, it rides great. But if I start it up, even on a warm day, without letting it sit, it will insist on driving at only 5 mpg for about two blocks and then....v-room!....it realizes that it's supposed to be driving and goes.

Is this a fuel injector problem? Or an alternator problem? Or a compression problem? And what can I do about it??