This is the first thread I've posted on here, but here it goes! I just purchased an '06 F150 STX with 35000 miles on it. This truck looks like it was extremely well taken care of. My question is this. I have no clue what type or brand of oil was used in this truck. Is it going to matter what brand I go with or if I go with a synthetic? Just want to make sure to get it right as this truck has to last me a long time!! Thanks for any help!