Ruby a 1990 240 flunked her emissions test today.
Codes 232, 113, 231, 112, 221, for last few days off and on.
Ruby is new to me, had been sitting for about a year unused.
No CEL until I cleaned the throttle body and AMM.
Then CEL began happening. Fuel consumption was very low before CEL appeared, now it is high.

I cleared the CEL before emissions test.

After emissions failed
I replaced spark plugs
Check engine light came on again after clearing it.
Swapped MAS/AMM
Check engine light came on again after clearing it.
Reinstalled the original MAS/AMM

Removed oxygen sensor and cleaned it with spray and disconnected battery for five minutes then reconnected battery. I cleared the codes.

No Check engine light, drove for about 15 minutes


Went for a short drive again and CEL came on about after five-seven minutes drive upon taking off from a stop light. If it is the engine temperature sensor that is the problem, shouldn't the CEL have come on immediately (the outside temp is 30 degrees here)?

Is my best bet putting parts one at a time from the ill 1990 240 onto my 1991 240, then driving the 1991 for about 10 minute to check if the CEL comes on? Then if no CEL returning that part back and then moving onto another part?
Should I try parts in this order?
AMM
Oxygen sensor
Fuel pressure regulator
Engine temp. sensor
ECU.


All advice is appreciated.

Joseph Segura in cold New Mexico