[sierra99]

Update.....This may help others...

I did get a o2 simulator and it did get rid of my 0420 code. But within 5 days, my CEL when on agian....no not a 0420 code but a 0171 and a 0174. I thought is was that fact that I was low on gas, but I cleared it and came back again. I finally had a time this weekend and cleaned the whole engine with gunk. I then waited for it to dry and then sprayed carb cleaner to check for a leak....no leak.
(no difference in RPM changes) I then pulled the pvc and checked for a vacuum in the engine case ( I was told that the intake gasket could fail on the inside and pull the pvc for a check there) But I then replaced the Pvc valve. I started the motor and the CEL light was off, and I did not clear it. It cleared itself. Truck runs real smooth at idle and in drive. I can feel a difference when I get on it.

Hey check the PVC and replace for $2.

Will keep updated. If I can keep the CeL of for a week, I will pull the simulator and see if that was the problem...