Note on Intermittents
WARNING: This page is about a different car, the 1990 Cadillac Fleetwood and 1990 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
Code E34 is usually set by a vacuum supply problem to MAP sensor. Check for proper vacuum routing for MAP hose connected to proper throttle body port, MAP hose chafed, pinched hose or cut hose. Apply vacuum to MAP hose at throttle body, and look for vacuum leaks in MAP hose or MAP sensor. Manipulate affected wiring and connections while observing ECM parameter P.0.2 jump or skip high with vacuum applied. The condition has been induced and cause of intermittent can be repaired.