gigispt,
I only disagree with Tim on one item in his critique of your ad. Your single long sentence does matter.
Make it easier to read. Lots of middle-aged guys with multi-focal lenses (like me) are only going to get a couple lines into that ad before deciding they aren't interested enough to read all the way through. I've never read past a few lines.
Capitalization and correct punctuation will make it easier to read and understand. You may not feel those things matter, and perhaps they don't to many readers, but others will give up and not follow up on your offer.
I still don't know what you want for it, if you have pictures, or even if it's a Chevy or GMC.
Help your prospective buyer decide they are interested. Don't put obstacles in the way of a sale, unless you, like Tim and I, want to keep your Suburban for ever!