1993 Chevy Silverado Still running Rich

I replaced the spark plugs and wires on my truck. It was stalling out and still is. It is have a roung idle and is running really rich. Before the problem started spark plugs and a fuel filter were replaced. The fuel pump is fine and the fuel line is too. I test the vaccum on it to make sure there weren't any leaks. But its getting better on idle but as soon a you take it out of park in to any gears it tries to stall out. I test to see if there was a piece of the fuel filter that may have got stuck in the throttle body but found nothing. What could be the problem?