1994 Ford Thunderbird engine smokes at times and check gaug

i have a problem that is stumping me. this car runs strong, at times engine will smoke, sometimes alittle sometimes alot, sometimes not at all. smoking seems to occur when idle drops slightly and check gauges light comes on. all fluids are still full so i cant figure this thing out, any help would be great. also check engine light does work but doesnt come on and its throwing no codes