2006 stx 118,000 miles 4.6 new air and fuel filters less than 2000 miles. No codes popping up. Sluggish when going then seems like it gets more power from time to time. Also changed plugs and cops around 5000 miles ago. Any thoughts on what to check would be appreciated. Thank you in advance.

 

Go to a muffler shop and get your cats checked for blockage. Check the backside of the FPDM (above the spare tire on the frame rail) for corrosion.

 

Also clean the MAF sensor. Do not use anything but MAF sensor cleaner... Many times a dirty or defective MAF can generate a poor performance condition without throwing a code.