Still trying to figure out my M50TU's deceleration to idle hesitation. My current theory is that it only happens when the DME tries to run in closed loop mode. I have all new sensors on the way, but help me make sense of the se readings before I go broke throwing new parts at this thing:


TEMP SENSOR measurements AMBIENT [acceptable range 2100-2900]
Coolant Temp (black) 5,570 Ohms
Engine Temp (blue) 2,006 Ohms
Intake Manifold Temp 1,768 Ohms

TEMP SENSOR measurements HOT (10 min after running) [Acceptable range 210-400]
Coolant Temp (black) 667ohms
Engine Temp (blue) 332 Ohms
Intake Manifold Temp 1,598 Ohms

Diagnosis:
The coolant temp sensor seems to be reading colder than it should. Ambient temperature was 80F, but it was reading more like 30F, and even when hot the coolant temp seemed lower than expected. This would also make the engine run richer than it should, especially on a cold start. Right?

FUEL PRESSURE (in PSI)

Idle 45
High RPM 45
Engine Decel from Rev 49 down to 40, back to 45
Vac Hose Off 52
Engine Off 40 (drops to 20 in a half hour, drops to 0 by the next day)

The FPR seems to be doing its job, but every measurement is about 10psi lower than spec. I've got a leak. But I don't see or smell any. All plugs are identically black from running rich, so I don't think the injectors are leaking (unless all six are leaking).

O2 SENSOR
Heater Resistance, but no voltage from computer to activate
Sensor Stayed around .18v, fluctuated only as high as 0.4v

DME may not turn on heater if it thinks the sensor is bad? Why doesn't it want to heat the 02 sensor?

Thoughts?