Afternoon

Have a 1988 d150 with a 6L( mild build. 222/224 cam 3200 stall longtube true duel. Holley terminator max x) with a 4l60e controlled by a holley terminator max x and a circle d 3200 stall and transgo hd2 shift kit.

Issue i am having is from a dead stop or below 20 km/h if I go full throttle it will pull until about 5500-6000 rpm, then act like it goes into neutral. Will only go back into gear if I stop throw it in park then back into drive. Will.shift perfectly after wards. Above 20km/h full throttle will.shift no issue.

Any insight to what to look for or try would be much appreciated.

 

I don't know anything about the holley terminator max but if this was a factory control unit I would say that your problem is in the tune.