We own a 1994 f150 4.9 manual trans engine the timing display on light reads constantly changing at idle engine warm 8 degrees to 24 very rapidly spout in place is this normal. Is this how computer is controlling timing at idle? I thought with spout connector removed timing should return to base number which is 10 and does not change. Any feed back will be greatly appreciated since our truck has intermittent miss and we have spent considerable time and money changing known good parts.

 

When you start the truck with the spout jumper connector removed, it should stay at whatever the base timing is set at. With the connector in, the computer will advance and retard it as necessary.