First off, yes I have done research and still cannot seem to find the problem. PLEASE HELP!

So the van goes into limp mode after driving for about 10 minutes or if I go faster than 50mph. I can actually prevent it from going into limp mode by driving a certain way. It's a 1991 Dodge Grand Caravan 3.3l AWD 150k miles. I am not throwing any codes/check engine lights.

So far here is what I have done,

-changed solenoid pack
-changed filter and fluid with atf+4
-changed both input/output sensors
-cleaned the grounds
-cleaned all plugs to sensors, solenoid pack, and TCM
-added new ground to TCM
-resoldered "factory splice" in the harness' wire loom
-reset TCM by disconnecting battery
-checked safety shutdown relay with multimeter and it looks fine
-checked TPS with multimeter and that looks fine

 

i had the same problem with my van. make a long story short, it was caused by a weak motor mount. when i turned the van a sharp left it would pull on the trans wiring, putting it into limpin mode. i ended up getting the connector from a salvage yard and extended the leads so from that time til i junked it i never had a problem with trans. the tranny was rebuilt, computer replace and various sensors by previous owner,never cured the problem. i bough it cheap.