Thanks 2 DXs' help. How much percetage it could be the problem of timing belt? If not timing belt, I have to let Ford dealer dignoze it because according to egg's suggestions, too complicated problems may involved,,
-ondway(一枫家新);
2002-1-24(#346081@0)
This sounds like a transmission problem. It happens when the automatic transmission changes gear internally and it happens only at a certain speed (around 30km/h).
-x2000(围城专家);
2002-1-24{50}(#346094@0)
You may want the dealer to check the transmission.
It should not be very critical. Maybe the previous owner has not maintained the car very well. The transmission oil should be changed every 2 years. Go to the dealer and ask them to check it when changing the oil.
-x2000(围城专家);
2002-1-25{92}(#346613@0)
Normally they will tell you what is wrong and its cost before they start repairing anything.
Thank u, buddy. I knew you r right. I remind I have just changed transmission oil at canadian tire 3 months ago. It could be problem they abused it? Never canadian tire unless you know some branchs are ok.
-ondway(一枫家新);
2002-1-25(#346845@0)
Results. The problem is not from inner transmission. The dealer adjust something (I forgot the name, like TV ~~ -- weird name) and charged me $130 for diagnosis and readjustion. It dispeared.
-ondway(一枫家新);
2002-1-28(#350301@0)