If a truck has a rough idle or misfire when the engine is cold but seems to clear up as the engine warms, a common cause of failure is the intake manifold gasket and intake manifold bolt seals. The manifold gasket and the bolt's rubber crush washers can fail and cause a vacuum leak which can cause the check engine light to show diagnostic trouble codes of P0171 and P0174.
Replacement intake manifold gasket set is a revised design with improved sealing over the original gasket. Intake manifold bolts are chrome moly black oxide hex head 6mm x 1.0 x 80mm in length and replace the OEM bolts.
When removing intake manifold for gasket repair, the knock sensors should be inspected for moisture-related damage. A faulty knock sensor can cause pinging, poor acceleration and a check engine light code P0332. Replacement knock sensors are available to fix the problem and RTV should be applied to the areas surrounding the sensors to prevent any further moisture damage.