I have a 99 4x4 4 door blazer. In the most of the time when i start it, the truck just won't go. There is no power, i have to drive half a mile or so before it will power will kick in. I can step on the gas the the rpm will go up but the it just won't go. A friend of mine said it could be a seal leaking, and until enough pressure if built up it wont go. Another guy say it could be the vacuum pump going. Took it to the shop they don't know what wrong with it. Anyone on here every experience anything like that? IF so any advice on how to fix it?

 

I moved this thread to the '2nd Gen Tech' so you may get some help faster. I also changed the title from 'help', which really does not tell enough to attract attention to your problem.

 

Sounds as though you have a transmission problem. I had a Dodge Ram pickup that had a problem after it would set for a few days. It was a check valve that was not sealing up properly allowing the torque converter to drain out. It would take an easy 60 to 90 seconds before it would even move.

I would take it to a transmission shop for diagnosis. If you still do not have an answer, then you may want to try some Lucas Transfix. I am not an advocate for the miracle in a bottle type products, but Lucas Transfix cleaned up the sticking check valve in the transmission of my old Ram.

 

Yes, it does sounds like a transmission problem from what you are describing. Possibly slipping, possibly losing the tranny pump or a cracked or broken sun gear.
You need to find a shop that has a clue...