O2 sensor light on 86 E300
After driving my car normally I noticed my 02 sensor light came on and stayed on.. When I shut the car off it stays off till I drive it for about 2 to 3 mins. At first it was once in a while, now it does it everytime.. I have been looking for the " reset " button near the battery under the cover, and haven't found one. The car seems to run fine, maybe down on power a bit in the begining when it first started to do this. I do remember once where there was a period of few days where when it came on, the car lost all power and wouldnt move.. but now ( months ) it hasn't done that.. It does had issues with a hard start. I cleaned the Idle control valve, made it better but when cold its had to start. That I am thinking is the temp sensor. when I pull the plug off the car once even run. Any help would be great, the car has 137k on it. Thanks!