B2200 Emission problem

Does anyone have any insight on how to make my B2200 pass Emissions at cruise?
It passes at idle, but not at cruise.

My HC and CO's are off the charts.

I think I need to replace the Mixture Control Solenoid.

Any help would be great!

Thanks!

Take that cap out! If you can.
Mike

First off, I take it that its carbed? Second how does it run at cruising speeds? Does it surge at all? I had the same problem with an 86 mazda that I used to own and I took to tons of different mechanics and all they did was mess with the mixture screw on the carb. Well that worked for about a day or so, but as soon as I went to try and pass SMOG it failed everytime. So I took it upon myself to rebuild the carb and it passed with flying colors and ran alot better than it had in years. I think the part that really made the difference though was the small pump thats located in the carb that regulates how much gas is dumped in the carb by throttle position. Also might want to check your EGR valve. It could be stuck. Hope that helps some.

Thanks,
I went ahead and ordered a rebuilt Carb from FL.
Everyone I've talked to, and most responses point to the Mixture Control Solenoid.
It doesn't surge at cruise, the truck runs really smooth and nice. But I am getting horrible gas milage out of it.
Well try this new Carb, and I'll keep this thread posted.

Thanks!