As stated, I am new to the forum. I have an '88 Ford F-150 w/the 4.9 straight 6 engine. It has 133K miles on it and still runs very strong. I bought it at about 119K and believe the truck/engine was well cared for beforehand. When I bought it, it had a sticker on the windshield indicating that on it's last Oil change, Pennsoil 10-30 had been used. And that's what I've used in it since, changing the oil at 4-5K. My driving is nearly all highway miles and the oil doesn't look very dirty at those intervals. Also, the engine "uses" about 1 1/2 to 2 Qts in between changes. I get the Wal-Mart special, $20. oli change and lube which uses Fram oil filters. 1st Question: Is Pennsoil a good oil or should I change brands. So many people have thier favs. What's the real truth? 2nd. Does it hurt an engine to change brands of oil? 3rd. At what milage, or when should I consider changing to 10-40 oil? 4th. Are there any additive I should consider using? 5th. Alot of bad talk about Fram filters. Whats the best one I should use? Thanks in advance.