1999 Ford Ranger engine running rough

I also have a 1999 ranger that runs rough and looses power, bucks when you take your foot off the gas. I changed spark plugs, wires, fuel filter, flexible fuel sensor. The ford shop checked it out and told me it could be the max air flow sensor by the air filter. They told me it would give them a starting place. Thats the first thing I thought of changing after plugs. The cost of finding the problem is getting so expensive I thought of using it for a boat anchor.