im considering buying a 97 f150 with the 4.6 and the seller says it burns 1-2 quarts between oil changes, any cause for concern?

 

I'd be leary of it.

But try to find out if it is a leak, or if it just burns it. Also how many miles?

I would keep looking around personally unless you really like this truck.

 

the truck has 84k, and appears to have been well cared for. the seller says it does not leak and i didnt see any signs of a leak. the truck is a loaded xlt ext. cab w/ofp and 4wd. its in great shape with a couple extras such as a cannister tonneau and cat back borla exhaust. the lowest he would go was 12.500, sound a bit too much price wise?

 

It's hard to say. I don't like an engine that burns oil because I don't like to add the quart in. Many trucks do burn oil and they run just fine. Ford considers less than a quart per 1000 miles normal, and this one is under that limit.

Burning oil takes a little bit of power away from the gas. There's less power in oil than there is in gas, and the oil uses up the oxygen to burn. Besides that, it's not a problem at low levels.

Most likely the ring pack is carboned up or the valve seals are worn, or both. Most likely both. If you like the truck you can clean the ring pack with two Auto-RX treatments expecting to cut the oil burn rate in half, but the valve seals, if worn, will need to be replaced or you can just live with it.

 

Most engines burn some oil when driven on long trips ask if he goes on weekend trips of 2hrs or more. My 98 with 150k miles
burns 1/2 of qrt /4000miles. My 92 302 with 130k miles burnt3/4 of a qrt.
I'd pull the plugs to see what they look like and maybe do compression check.