D0123 and Kurt’s Iidea of disconnecting the 02 sensors temporary is a great idea, I’ve run into the same 02 harness plug corrosion/bad connections causing intermittent running conditions, they look fine until pulled apart.
Your Motor idle/run better when cold, get worse when hot? I recall you mentioning it was test driven cold, so you didn’t get to see the issues when hot.
The MAF & TPS are used, but 02 sensors & a few others are temporarily unused (open loop) until the operating temp is reached,the remaining sensory data inputs/outputs then come online as the ECT relays coolant temps to the EEC..(closed loop).
Good reads...
Meant to ask, any internal motor mod’s you know of, e.g. Aftermarket Cam, Heads, etc? If uncertain, did the motor run with an equal sounding lope at idle- when it ran its best? Still wondering why the chipset’s in the EEC.
Shop still have the car, back home yet, did they find anything useful?
Best of luck!
John