I have a 05 Screw thats 4x4 with 5.4. I have noticed here recently that while im in o/d lugging up a hill if I ease into the gas my truck feels like its slipping or kind of a bump(it shakes the whole truck) until it downshifts or I let out of it. It does not do it all the time but somedays it will do it more than others. Any ideas?

 

More likely a misfire - how many miles are on the spark plugs?

 

there is 87,000 on the truck. I got the truck when it had 54,000 on it. I dont think the plugs have ever been changed.

 

It's overdue. Ford is recommending 60k changes now for the 3v, and be aware of the sticking/breakage issues. Those are the exact conditions where a low grade misfire is most noticeable.

 

if it misfires wont it throw a code though?

 

Not all missfires will throw a code. Sometimes it takes a while for the computer to catch up. Could also be a coil going south too. On a rare occasion (haven't heard of to many) the fuel pump could also be starting to go south causing a lean missfire until it builds up enough pressure and the truck then finally will downshift.

Either way I would pull some plugs and check for carbon tracking on the boots/plugs. I would also change out the plugs reguardless at this time due to miles. You can also go to a local auto zone or some place that will scan the computer just to see if there is a pending missfire code that the computer has yet to turn on the MIL light for.

 

Low grade misfires generally won't trip a CEL or throw codes till they become consistent hard misses. At 87k your plug gaps are probably getting pretty wide.......

 

Hey have same problem, have changed plugs 84,000, 6 out of 8 broke,,still has the mis or what ever the stumble is. Fixing to change fuel filter. No CEL either,,

 

YOU may need one or more cops.

 

My plan was to get plugs,cop,wires, ect. changed when tax cash comes back. I hope I can make it a few more weeks. should I replace the everything with stock parts or is there any upgrading that wouldnt mess anything up?

 

Motorcraft SP-507 or SP-515 plugs. Start with those. If it still misses, then we can look at some cops.

Again:

 

Same exact problem with my truck....just bought the truck last week: 07 5.4 3V with 77,000 miles on it. When in O/D at about 40-45 mph (~1500 rpm) I accelerate slightly thereby lugging the motor and I feel a shutter that feels almost like I'm hitting a pothole. I'm buying all new COP's from Global Auto on Ebay and I'm going to change plugs too. I will report back with results...

 

Im getting the stealership to do it. I asked about them breaking the plugs, if I would have pay to remove it and they said no. I said good b/c I bring it to yall b/c they are SUPPOST to know how to get them out with out breaking any.

 

I still have the miss/shurtter feel also,,,looks like COP's for me to.

 

This sounds a lot like the old torque converter shudder that my 95 Mark VIII experienced. A trans fluid change fixed it.