RENIX Computer Swap '90 into '89 ?

I have an '89 that I'm keeping, partly because it doesn't overheat. It has a "surge" when just cruising along 35~45 mph. I've swapped out all the related sensors including Oxygen sensor, got it to pass CA smog, and generally spent too many hours on it.

I have access to a '90 that overheats and has other RENIX typical problems that I don't want to deal with again, so it will be sold to the state as a "Gross Polluter" for $1000- after pulling all the parts I can legally remove.
Otherwise the '90 runs fine and has always passed smog on the first try.

Here's the question; Will the Engine Computer swap directly from the 1990 into my 1989?
Anything else I should change over while I have the chance.

Both Cherokees; 6 cyl., AW-4, 4x4. Donor '90 has factory towing so I'll check the axles for 3.77 gears.

Thanks, Mike

It should - as I recall (per Hollander,) the ECU for the I6 is swappable 1987-1990, as is the ECU for the I4 gasoline engine (you just can't swap the I6 for the I4 or the other way round - the injector driver outputs will be wrong.)

The TCU was separate until sometime around 1995, so that's not at issue.

Your tow package may be 3.73 gearing, which is only nominally better than the 3.54 behind the AW4 (the AW4 is actually nicely complemented by the 3.54 gearing with tyre sizes from stock to 31", I've noted.) However, if you do have 3.73 gearing - I may want to talk to you, as I'd like to get quit of the 3.07 gearing in my 88. I'd eventually like to go with 4.10/4.11 or 4.55/4.56, but that's a way down the road (and probably not until I can score a set of D44 axles anyhow.)

Bad TPS or brake switch tripping the TCU TC lock up would cause the surging.