Originally Posted by MrB
It does it intermittently whether driving at speed or idling although I figured out how to make it do this anytime by getting on the brakes hard. I changed the brake booster but didn't help, it will still do this with the booster unhooked. I guess I'll try the crankshaft positioning sensor next.
If it dies when you hit the brakes, I would say you probably have a vacuum leak somewhere. You can look for leaks by spraying carb cleaner near all the vacuum lines/pcv/intake, and listening for a change in engine sound. For safety sake do this on a cold engine, and have a fire extinguisher ready... just in case. Disclaimer: Myself, or Ranger-Forums don't take any responsibility if you catch something on fire
I had a pretty bad vacuum leak on my truck, and found/fixed everything like this.