I recently had my check engine light come on in my escalade. i went to the auto parts store and had it scanned, it read mis-fire no 5 cylinder and radom mis-fire. i just changed my plugs and wires about 5k mles ago, ac delco plugs 41 110 gaped at .40 and napa auto parts wires. i had ac wires but they were gg when i needed hh . i purchased them on line and had limited time to service my ride so i just went to where i went and purchased those wires. my question is what is the best way to trouble shoot the problem ? as far as if its a plug, wire or coil pack.my other question is does any one know which cylinder is number 5 ? As far as symptoms im having with my truck is mostly an occasional rough idle and it seems my truck is burning more gas than usual that started a couple of weeks before the light but along with the rough idle . any feedback would be great thanks in advance.