i have a 2000 durango with a 5.9 and it was misfiring bad it was so bad it was almost undrivable the codes came back to #1#2#6 misfiring and a miltiple misfire code i did a compression tast and #1 was 124psi and the rest were about 150psi so i pulled the heads and there are small cracks on 3 cyl between the valves ......so i was wondering if i should spend the $900 in new heads because on the small hairline crack