kevinek

Ok I need some help here. Its not my camaro that's the problem but I don't know where else to post. I have a 91 gmc 1/2 ton 5.7 auto. My problem is I keep failing emissions for too high of hydrocarbons. My current reading is 265 anything over 126 fails. My first thought would be the cat but the tech at the station that did it said since all my other numbers were very low he swears my cat is fine. It also has a rough Idle that the tech said is probably the reason for the unburned gas (hydrocarbons). Here is what Ive done so far.
Full tune up, cap,rotor,wires,plugs,fuel filter,pcv valve
fresh oil change
checked vacuum and the gauge holds steady at 20
checked timing. It was 3 degrees advanced than what the factory calls for So I set it back to factory specs
changed egr valve
Used a jumper wire in the dlc and the only code I got was a 12 which means everything is good and there is no stored codes.
Checked compression with warm engine and plugs out with throttle open. Compression was too high 195-205 not sure what would cause that?
replaced 02 sensor
My next step is to change the cat even though 2 inspection stations said the cat is fine.
I'm in a rut here because this truck came from out of state and I cant even get license plates in Texas without passing emissions first
The truck runs like new other than the slight rough idle.
Any ideas? tHIS IS DRIVING ME NUTS