89 f150 wont pass smog

I have an 89 f150 it passes on everything but CO at an idle it has all new vacume hoses plugs and cap and roter. The check engine light isnt coming on but when i check for codes i get a code for EGR input to high. After the first test i replaced the thermostat because the truck was running at 120 deg or lower runs at 190 now and ran a bottle of that guarrenteed to pass stuff through it and took it back and they said it was blowing higher CO than the first time anybody got any tips I havent done anything with the EGR code as the guy at the smog shop says The EGR wouldnt affect the CO at an idle MIKE