I have a 2000 with a 4.2 it has 12k miles on it and it has developed a rough idle.

It is not rough enough to effect the tach but you can "feel" the miss at idle. Beside this problem it runs well.

Just returned from the dealer they hooked it up and said " nothing is wrong all sensors are within tolerances" and that " 4.2s are somewhat known to idle rough"

So, I have 2 questions:
1. Is this a common problem with 4.2s?
2. What should I try next?

Thanks,

DaSmitt