3.0 v6 running rough

I chased problems with my 2003 Ford Ranger XL 3.0 for a long time and replaced so many parts, to deal with it running so badly until it barely could drive at all, spending literally thousands of dollars to get it running again. I'm hoping that by sharing this, it might help other owners of Ford...

so i have a 99 ford ranger 3.0v6. running not too rough at idle but enough for me to notice... then when accelerating it runs even rougher and is really doggy... kinda like a diesel with no turbo... no check engine light, and put scanner on it to check for pending codes but none appear... pulled...