I had a hesitation problem with my '01 SCREW with 4.6. Shortly after startup and going down the road, the truck would stumble upon acceleration. I could give it more gas, but it would not immediately recover. It seemed like no matter what I did, it would not accelerate. This would last about a second (I know it doesn't seem like a long time, but it is an eternity when you pull out in traffic and your truck refuses to run). It continued to do this intermitingly and to a lesser degree once warm.

I have solved this issue for my truck. The problem ended up being a bad Differential Pressure Feedback Exhaust Gas Sensor. This sensor determines the amount of exhaust flow back into the engine as part of the Exhaust Gas recirculation system. If the sensor is bad, it can flow excess exhaust gas into the engine, and as you might expect, cause a hesitation of the engine. This is apparently a common problem with Ford trucks since Ford has redesigned the sensor. The new sensor is noticably different from the old one, and cost about $31.00. You will find the sensor on the drivers side near the firewall. It is attached to two tubes that come off of the exhaust down pipe.

Since the problem was intermittent, there was never a code set. I guess it got to the point that it happen so often that a code was finally set. It took 2 years! Upon replacing the sensor, the hesitation problem disappeared.

Hope this helps someone else.

 

thanks i have the same problem happens when its cold out on cold starts at stop lights/signs. i will get my sinsor right away 98 f150 xlt super cab 4.6lt

 

Happy you got a fix but that is not the way the DPFE works if you care.
The PCM controls the EGR operation.
The DPFE a(differencial pressure sensor) does not control anything but tells the PCM the state of the flow by measuring accross an orfice inside the big part of the tube. This indirectly tells of a pending problem with emmisions due to low flow thru the EGR that can't be monitored any other way in this system.
It was mandated by federal EPA as early and 1996 to meet the OBDII rules.
If for instance the DPFE failed and there is no real flow problem, the sensor failure by it'self would not affect the engine operation since it is only a "specific" monitor function only, when the PCM calls for the test to be done and that is only once per drive cycle and not a continious function..
Been there already with my truck.