89 cavalier runs rough when hot

[eugerspeed]

Chevy cavalier, 1989, 158,000km's, auto, 2.0L ; I recently did a desperately needed tune up : spark plugs, air & fuel filters, pcv valve, throttle body clean, lucas fuel system treatment, coolant & thermostat, tranny fluid & filter and it ran great for around 300km's then started a problem.

When cold the car runs great and as the car reaches a certain operating temp it develops the following symptoms. The idle starts hunting roughly with the rpm's low enough to barely keep it running in park or drive. When you pull up to a stoplight the car will sometimes stall, but it always starts up again. Then when you hit the gas it'll stumble/hesitate throughout the rpm range UNLESS you have WOT then it pulls strong accompanied by blue smoke. I also noticed a smell of gas in the exhaust telling me that it runs rich.

When checking the codes I get 33 and 45, so before I start throwing sensors at the thing, what can I do to pinpoint exactly what is needed?