Hey guys,
I am having a problem with a part throttle surge/bucking on my 2002 Exp 4.6. Problem is intermitten, tried driving with a code scanner installed when problem popped up, no codes where recorded. It happens when you start off from a stop and accelarate up to cruise speed vehicle sometimes vehicle will surge or buck then level off. If I floor it vehicle acts normal. Ford just replaced fuel level sensor and flashed the computer. Problem was there prior to this maintance. Just replaced the TPS and cleaned IAC went good for a week wife said it tried to cut off turning a corner????? Help
Po

 

Some things that come to mind are IAC valve (you mention cleaning, that didn't work for me so I replaced), TPS, MAF sensor, and PCV hose. Could also be a bad coil pack or two.

Good Luck.

 

I was going to mention that I had a similar problem when my alternator had about 1 week of life left in it. It's a less likely solution, but throwing it out there anyway.