1995 Dodge Caravan at a loss

I was driving my van and came to a stop sign to make a left turn and when I went to turn the van would not push over 2000 rpms and had no power. I could barely get to 20 miles an hour. Then when I get to the bottom of the road it acted fine. But when I pulled on my street it started doing the same thing. Its got me baffled and aggravated so if you can help will gladly take all imformation.I dont want to replace one thing and that not be it