Hi All,

Just gone through a week of doing work on my 92 3S-GE MR2, doing a whole lot of maintenance to fix oil leaks, replace timing belt and clutch. But throughout trying to resolve an issue where it is hard to start, won't idle, and dies/stalls at 2500rpm and won't recover.
 
Working through it, the dizzy cap and rotor had a lot of pitting, so I thought I'd found my problem, but once all back together it is still there.
 
What I've done is:
New timing belt
New clutch
New crank seals and oil pump seal
Injectors cleaned and tested
New dizzy cap and rotor
New leads
New plugs
Tried another TPS
 
I'm totally stumped as to what the problem might be. Anyone got any suggestions?
 
Kind Regards
Nathan

Do you have a service manual for the Gen2 3SGE?
Download one at: https://www.sq-engineering.com/wp-content/uploads/2018/11/3SGE-workshop-manual-early.pdf
Lots of tests in there for the EFI system.
Check out and test the idle speed control.  Page EG258 
Make sure all the small diameter hoses are connected properly
ACIS, vacuum tank, VSV's, fuel pressure regulator. MAPS etc.
Good luck with it.

If all that fails, it may be well advised to have a very close look inside the ECU.
Capacitors can go bad causing strange symptoms as you describe.
Often evidenced by leaking and discolouration onto PCB.

The most critical thing in you list of things you have done is "New timing belt"
In my opinion this is quite a tricky job to do.  I have read of many people getting this wrong.
 
I would do a cylinder compression check to see if it comes up to specks