First, did you ever buy a repair manual for your pickup? You really need one if you are going to do maintenence yourself. It will pay for itself in no time at all. Usually about 2 oil changes. Watching the guy at JiffyLube is not the way to learn.
Second, beware of a cure in a can. For the most part they will do more harm than good. If you have a high milage engine, using a motor flush can be counter-productive. Removing varnish deposits and gunk in a high milage engine can lead to compression loss and speed up engine wear.
Don't become dependant on these "miracle" products.
Third, if you are going to use them, follow the directions. If it says add 10oz to a full tank of gas, don't dump it in a 1/4 full tank. Too strong of a concentration can make combustion temps rise and lead to burned pistons, valves, rings, ect. Make sure you use a good upper cylinder lubricant like Lucas, RedLine or Marvel Mystery Oil after you have run a tank of gas treatment.
Regular oil changes and consistant maintenence are the best method for long vehicle life. If buying a $5 can of magic worked, everyone would still be driving 20 year old cars that ran like new.