I just got my 87 bird with a 383 lt1 and 4l60e out for the first time on Saturday and when driving to the track I noticed that the torque convertor was trying to lock for breif moments but would not on completly like it did last year.

Over the winter I put a 9" rear end changing the rear end gears from 3.73 to 3.70, could that effect it? The car has a edge 3300 stall that is two years old.

The only other thing I could think of is that it could be cause from the car not going into closed loop because I run it without o2s to keep it in open loop because it surges and goes lean at a constant speed? I know I need to get the thing on a dyno and not just keep gettting the mail tune, but I ran the car this way last year and the convertor locked?

 

any one?

 

Assuming your using the 4L60E factory PCM you may be getting intermittent misfires this will cause the converter not to lock and running lean will cause the misfires. Thats the most likely reason for the intermittent occasional lockup