I am looking at buying a 2002 ecsb 4x4 auto it has 163,xxx miles It will be puling my 31 foot camper in the mountains. It has a homemaid strait piped with an airdog 100 and a airraid intake. I donno if it has a programmer on it or not I cannot find anykind of box in the truck but it does roll a little black smoke when u get on it. I have looked everything over best I could tranny fluid looks good with no burnt smell but does have a big 5th wheel plate in the bed. I have done the paper towel test on the oil it has no halo that I can tell. Is there any other way to check the injectors out I know they have had problems in the past. Is there anyway to tell if the injectors have been replaced before? Carfax has nothing on it but yearly tag renewals. HE wants 12,700 for the truck 8 of 10 on exterior and interior. WHat do you guys think? Is there anything else I should pay close attention or look at? sorry for the long post just want to make the best buy I can.