Hi. Having problems with my F150 4.9L. Will start and idle fine but when I take off it will sputter and blows black smoke until it stalls or cleans up and power returns. Only to happen again at the next stop and take off. If I let the truck run for 15m or so the problem is gone. I’ve started just letting it run for 15m before I go anywhere but this is costing me a lot in gas. Any help or point in direction would be greatly appreciated. Oh yeah I've done a full tune up, so it's not the plugs.

 

There are a number of things that could cause this and a fuel filter in not one of them.
The fuel pressure regulator allowing to high a pressure.
The OX sensors are very slow reacting (the heating you mention) helping.
The ECT and IAT faulty. These still have a large effect on fuel at all times.
Any fault that suddenly makes the injection go very rich (the black smoke).
You should have a fault code stored with this kind of problem.

 

Thanks bluegrass - I stopped to have the codes checked but the 3 places I went to could not test my truck cuz its a 94. they could only do 95 and up.