Check and change the oil reg. Change fuel filter reg. Do normal cooling system flushes. When to do these depends on how you use your truck. I change my oil about every 7500 miles. Fuel filter twice a year. Cooling system every 3 years. You might also want to run some fuel conditioner once in a while. I carry anti gel additives in the winter. You might also want to carry a spare crank sensor as they have been know to fail and leave you stranded. I have only had one fail in 130,000 miles.