Just got this trooper. 120000 on it. Problem started randomly. Runs like a champ until operating temp is reached and then bucks and hesitates when you give it gas. It will ride fine with light gas pedal pressure but as soon as you try even a gas it bogs and bucks. So far I have done new plugs, fuel filter, egr, pcv and inspected vaccume lines. Still have the problem. There are no codes or lights. I have spent hours searching forums trying to figure this out. This seems to be the "spot". Look forward to hearing from anyone with their 2 cents.