The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
99 through 05 GEN III truck engines may experience any of the following:
The intake gasket seals may be leaking around the intake ports, causing a lean condition. The intake gasket seals may leak around the bottom side of the port, making it a challenge to detect the vacuum leak. The technician may also notice lower than normal MAF readings if the intake seals are leaking.