The problem is only sometimes other times it runs perfect. After driving continuously for at least 15 minute it very rarely runs bad if at all. The transmission was changed a little over 1000 miles ago. I have change the fuel filter, fuel pump relay, fuel pump, gave it a complete tune up, used a scanner tp check for codes and there is one p1810 transmission pressure switch and I'm not sure if that has anything to do with it. What else can I check or replace?