Went to start the truck and it acts like the throttle is wide open. Any suggestions for the cause? I am LOST on this one  

please any suggestions. All are welcome and none are stupid. I am new to diesels and need help!!!!!!!!!!  

It actually could be a stuck throttle. Make sure that it isn't. Follow the throttle cable all the way from the pedal to the injector pump and make sure the return springs are there and in good condition. Make sure that the cable is actually connected to the pump AND that the cable moves easily/freely both ways when you press and let off the pedal, (with the engine off).

Also, when a diesel is getting only a partial fuel supply, it can "over-run". If you've ever run one out of fuel, you'll know what I'm talking about. Make sure that there is no obvious fuel leaks or any places where the fuel system is sucking air. ANY fuel leak, ANY tiny bit of fuel showing anywhere on the motor is real cause to find out why and fix it. If so, tighten that line and try it again. In fact, since these motors vibrate more than the gas bombs, it doesn't hurt to grab an open end wrench and tighten up any line that you can reach, once in a while. Do it every time you change oil, as well as look it over carefully for anything out of the norm, and it will save you mucho aggravaton down the road....

Be VERY careful, if a diesel ever gets into an over-run condition, the ONLY way to stop it is shutting off the fuel, electrically or manually, but DO NOT let it overspeed, NEVER, EVER!

One last thought, there is a cold start solenoid on the top of the injector pump, check to make sure that it isn't somehow screwed up, (although I'm not perfectly certain that it could/would cause an over-run condition).

Just had another last thought! Get some "PB Blaster" penetrating oil. Squirt the hell out of the top of the injector pump and all the stuff attached there. I just remembered, my truck did that one time, but it had been sitting for about a month in the freezing weather and there was corrosion in that area. The Blaster will free ANYthing up, plus it leaves a thin coating where ever it's been sprayed. That doesn't mean that you don't have to get in there and clean it up properly, it's a temporary fix. Clean and grease as necessary...