Trace the 2 main vacuum lines where they connect to the top of the UIM. 1 runs to the brake booster and the other runs to a main vacuum junction between the firewall and the motor. My guess is this is where you'll find trouble. Also check the neoprene tube which connects the PCV valve to a fitting directly below t-body bolt up on the bottom side of the UIM. Mine was cracked.

Redcoat Raceworks. Performance parts and custom fabricating for Contours, Mystiques and Cougars. Specializing in chassis and suspension parts. Custom end links, control arms, strut tower bars, engine torque braces, etc.