track_mr2 , I think you may have mis-interpreted my post.  Terry is a busy man, not only does he have a workshop full of customer cars to work on but he also has to deal with customer "issues".  In this case he took the time to give us more of the background to this story.
 
From what he has posted I'm seeing a car that had a previous idle problem, seemingly related to the air-con system.  After fitting a used engine/transmission package (customers decision) plus "other work", the customer initially OK'd the result.  A "few" days later (and I'm going to presuming that was a few days of driving) he then spent several hours trying to track a recurrence of the historical idle problem - at no extra charge to the customer.  He couldn't find the fault (possibly because as is often the case the car behaved itself in the workshop) but used his experience to propose a possible cause and solution, e.g. the idle control valve.  He has also (obviously) advised that in this case a new part from Toyota will be preferable to used - and he would probably have a few of these on the parts shelf.
 
Now both he and the customer are at the mercy of Toyota's supply line, and I know what that can be like.  No joy, he advises the customer and the customer decides to cancel the order.  Fair enough.  What I don't think was fair was at no point prior to Terry's reply were we told about the historical idle problem or the parts delay.
 
Also, Terry's explanation about wanting the original ECU sounds perfectly reasonable.  He wants to make sure that the replacement part he is sending is the right one.  And I've not yet heard if the replacement was going to be free of charge under warrant or not.

^ wanting the original ecu is more than reasonable. Reality is, the faulty part responsible for the idle issue was the ecu R&T provided, so therefore should be made right by R&T. Most workshops wouldn't fork out as I suggested, but some would & in principal it's fair.

There was nothing wrong with air con its brand new. Terry thought it was an air compressor that was leaking gas and should be replaced and will be cost me $1500. At the time I cannot afford it .. I just want engine and gearbox running so I can drive it.
Terry said ok no worries he will regas it and O ring it….  But its still leaking gas and realised that the electrician must have missed this so he was called back to fix the wiring.  Then terry regassed again and $100 out of my pocket. He also put double O rings on it.  Problem solved and still working fine since.  So the compressors fine…..
“after various emails, customer agreed to have us order a new  throttlebody idle control valve which she would pay for and  we would fit at no charge.”
I was waiting for a month about this then I emailed you 3 times with no reply then you finally replied after I sent a concerned email and you said in few words that you haven’t heard from japan Toyota. So I suggested to forget it and cancel cos I knew its time wasting.

The reason why I started this topic is because youre not replying to my emails that I have sent many times to sort this problem … and I thought and felt like youre avoiding me and want nothing to do with this.

At the end it’s the ECU that’s the faulty of all this dramas. I have sent you an email two days ago to discuss in privately to sort this out. I haven’t heard back from you. So I will send you another email again today. So Please respond.

Altho the ecu is from a uk vehicle, i would try it. Plenty swap jdm and adm ecus around. Just becuase there is a diff in the part number doesnt mean internally its different. Or it may be a minor difference like one is for an egr equipped vehicle. But nothing that effects the running of the engine.

I'm going to lock this thread now. Everyone has had their say and I feel it has all been balanced and objective.
I stress to everyone that unless you rebuild absolutely everything, you should expect issues when fitting used parts.
The only solution to fault find issues like this is to change components one by one until the problem goes away. Cars are complex machines and even the experts have trouble finding the cause of faults.
Peace