So my 2004 5.4 3v 4 x 4 with 90k has been bogging down intermittently for the last 3 weeks and now it is consistant at low RPM. It will bog down and then throw you back in the seat. Yesterday taking off from a stop light, I thought it was going to die. Again yesterday, I am on the highway doing about 60 mph and I floor it because it is bogging again. I hear a clank clank at about 4,000 RPM with the tach jumping around. It did not feel as the transmission was slipping. Could this be a bad misfire or is it the transmission? I am getting no CEL's and tried scanning for codes with nothing coming up. I also have never changed the plugs and transmission was serviced at 36k and 74k with motorcraft atf.

Thanks in advance guys, if you have any ideas!

 

I can guarantee you that you need a new set of plugs, & possibly some new cops!....Especially at 90K!

 

Sounds a little more serious than a set of plugs and COP's.

I'm just going to take a shot in the dark and say cam phasers?