SC300 ECU problems

[sexyrexy71]

I have a 95’ that is an otherwise magnificent car but it eats ECU’s. The original unit has been repaired twice but it runs like crap, I keep it as a last ditch get home spare in the trunk. I bought a unit outright from All Computer Resourses for $650,  at first it would not shift int overdrive, I sent it back, they fixed it then it failed after the warrant was up. I sent the original unit to SIA Electronics for a $150 repair, it failed after awhile. I took my original and the ACR unit to Car-Computers. Com in Stockton, CA which is a short drive from home, spent $600 and both units failed shortly afterwards. I bought a junk yard unit out of Las Vegas on ebay for $150, it actually never has left me on the side of the road but now refuses to go into overdrive. It resides in my trunk as a second spare. My latest, ECU #4 is from Pro Module Repair in Van Nuys, CA. It runs great but is now only momentarily shifting into overdrive then shifting out. This car is very low geared, it needs overdrive bad. These cars have two ECU issues. The worst one is they just die in traffic and you have to swap ECU’s on the side of the road. I have become very adept at it! I have had two units do that to me. The other is the refusal to shift into overdrive- I have seen three do that now. I know about the capacitors going bad. I had a failed tachometer thatI think may have contributed, my instrument cluster was repaired by Tanin Auto Electric. I had to replace the distributor twice because of failed pick up coils. I have several ignition modules that have been swapped in for troubleshooting. I even replaced the two wires that go between the ECU and Ignition Module. Its a real saga, only a dedicated mechanic and electrician like myself could deal with this. Does anyone have any advise or experience with these issues?