I have an 07 burban we bought last year. It had a rough idle and the check engine light came on. They went over it and found 1 and 4 needed replaced. In October we changed all of the wires and plugs. Recently it has started a rough idle again. We have cleaned the MAF sensor, air filter, and throttle body. No codes yet but I'm concerned about getting stranded with 4 kids. What else can we try before spending a fortune at the shop? I have noticed it doesn't rough idle when on an incline in my driveway. Also decreased mpg from 12 to 10.

 

Not sure what the incline has to do with anything, maybe just the way the engines internal weight sits differently, but at idle sitting in the driveway the engine has no load so you are not likely to feel a miss or poor performing cylinder as the momentum of the piston moving in the bore is masked.
You will need to have a compression check done to see if one or more cylinders may have bad valves or possibly the AFM failure... if compression is good, I would have the fuel system serviced, i.e. injectors cleaned, then move on to new wires and plugs then coil packs.
the items that cause a miss or rough idle are lack of , fuel, spark or compression, the rough or poor idle is a result of more than one cylinder suffering those conditions.

 

if you have access to a scantool check the fuel trims and misfire data, if you don't first thing i'd do is inspect the spark plugs and wires