88 Trooper 2.6 Won't Start

Drove it into my garage, removed the air filter (including the air sensor plug), removed and inspected the spark plugs, put them back in, and put the air filter with smog hoses back on. Now it just cranks. Could a vaccume line cause this problem? OR the sensor on air filter assembly? It has got to be something simple missed. Any pointers would be greatly appreciated.