My son has an 06 XLT 5.4 SuperCab with a lift (not sure how high). 20 inch wheels and tires, runs and looks great. Get a slight surge/hesitation when accelerating frequently. Could this be a U-joint? With a lift it's probably prone to wear U-joints quicker. Any other ideas?

 

A surge would have me checking the plugs, air filter, trans. If it was u-joints, you would feel vibration or hear noise.

You can also put it in reverse then drive while holding your foot on the brake to hear any clunking. Also, lay under truck and try to turn drive shaft by hand and note any clunking or excessive play.

Can you describe the surging more?

BTW, where in MN are you?

 

We are in Chaska, MN. I guess he says it's more like a clunk/slip. Shifting seems fine and no spike in RPM.

 

A clunk and then a slip?

I would try what I had suggested and see what you come up with. Slipping to me sounds like trans. Check the fluid on a level surface with motor running and up to operating temp. Yellow dip stick on pass side near back. Do use only Mercon V ATF.

 

Trans fluid level fine. Even looks very clean. Hopes it's not plugs, they are supposed to be a real pain on the 5.4. Idles really smooth so fouled plug is doubtful.

 

It could be a TPS sensor on the throttle body. Does it feel like the tranny is lagging behind your gas pedal commands? So when you let off the gas it will surge then clunk?

 

You can try to reset the tps.
Turn key on(do not start)
Wait for idiot lights to turn off, like 5-8 sec
Press pedal to floor slowly
Quickly release
Turn off
Start truck and drive.

 

Thanks, will try that re-set