2003 Avy

[importkiller76]

Ok so I found an Avy for crazy cheap locally and am gonna go look at it. I've contacted the owner and she said it's in pretty good shape inside and out (looks that way from the pictures as well but for the price she wants it doesn't really matter). She said once it's going it runs and drives fine but won't idle properly. It's a 2003 Avalanche presumably with the 5.3 with 200,000 kilometers on the clock. I'm gonna go drive it and see for myself but before I go any possible causes of poor idle?

[AirForceAngler]

Many and varied. Bad injector, vacuum leak, egr, plugs/wires. Is the CEL on?