Hi All,
Newby here, name is Bud

I have recently completed a motor swap on a 94 4x4 Ranger and something is not correct. The original motor was a 4.0 and the donor vehicle was a 93 4x4 with a 4.0 so I figured this was a no brainer...... Oppsy.........
The trannys are the same (both AL4D) and all accessories A/C Alt etc were kept with the original motor and just dropped in the whole ball of wax....
The first test drive I noticed some really poor performance in the mid power range and somewhat poor everywhere. Checked the Engine control computers and noticed they were different versions. Swapped the computers and performance made a marked and very noticeable improvement but still not at 100% especially in the 1/2 to 3/4 power band At times it will take off and run perfect. But soon it will revert to less than perfect, for no apparent reason..... It also feels as though there is a pronounced miss in the motor most of the time, if I mash the pedal it usually helps but then starts missing again when I back off it. I have not been able to get any real pattern to it all, except it always starts to miss again once I back off the trottle all the way. My last test drive I also noted the temp gauge started varying quite a bit, up all the way, then back to the middle and so on? I checked my coolant and it is full, no aparent leaks...... Any help out there?