1994 Chevy Blazer mileage: 105,899. I have a 1994 Chevy S10 Blazer. It has been running rough lately and a lot of fuel has been coming out of the tailpipe and the smell of fuel is very extreme. I have had it put on the computer to check everything. My husband has changed all the spark plugs; the left side was bad, the right side was good. We even had the fuel injector cleaned. But when we did this it really started to run rough. Any suggestions on what may be causing the problem? I am putting too much money out for fuel lately.