1995 Chevy Blazer

You are running too rich, either an 02 sensor, MAF sensor or stuck innjector, but if the service engine light is on lets read the codes as a first step, here's how:
Cross these two terminals as shown with a piece of wire, then turn the key on. Count the flashes, a 22 will flash as 2 flashes then a short pause, then 2 flashes, if more than one code is stored, the pause will be longer. The codes will display three times and end with 12. Write them down and post here. This connector is right under the middle of the dash...