Clean the connections on the coolant temp sender AND especially the
connection to the oxygen sensor. After a thorough cleaning AND drying,
coat the connections with dielectric grease and reconnect. Good chance
the problem will disappear. Moisture in either connection gives
incorrect readings to the ECU.

Karl

Mark Tuovinen wrote:

>> My 87 Westy has a power loss problem. It occurs when the engine is
>> cold and the engine is damp (from recent rain or high humidity), and
>> lasts (usually) for about 10 minutes. As I accelerate (partial or
>> full throttle no difference) the engine bogs and looses power. If I
>> shut the ignition and turn it back on, the problem clears....and then
>> comes back until I've driven for 5 to 10 minutes. It also happens
>> when the engine is warm and I'm driving through heavy rain.
>>
>> Anyone know what the problem might be, and what can be done to fix it?