so my uncle has an 06 with 100 k. he was pulling his camper that is under 8000 pounds. said it would not go faster than 30. then after awhile he got to 50. said it dd it last week unloaded but once he let off then on again it was fine. he is thinking fuel filer. any ideas???

 

what mods have been done?? if the truck is limited to speed sounds like it went into limp mode....