What year is the engine? I have had three of them. My 2002 Jeep has a 4.7-HO, I had a 2005 Durango with a 4.7 and my 2008 Aspen has a 4.7 "Semi-Hemi", as it was called internally when they changed the heads, spiked the HP. All of my 4.7s were great engines, but the Aspen really lights them...