2.0i engine problems

[929-2.0iHB]

Car:'86 929 2.0i HB
Engine: EFI 2.0 4S SOHC 120shp

I have a couple of problems with the engine...

1)
The coolant temperature sensor is probably defective
After taking it out and thoroughly cleaning it I did measure
the NTC resistance at -20degC, 20degC, and 80degC... and its
WAY off what is stated in the workshop manual. Also it outputs
a very slight current, about 4uA.
This current indicates my ECT has absorbed some water and is
outputting a galvanic current along with the resistance and pushing
the apparent resistance out of spec.

Other ECT sensors (from the bone-yard) were measured for comparison
and they did not put out any current.

So I got a new after-market sensor, not OEM they are not available.
Looks the same and fits in the engine. Measured this one also and
it has resistance values that are totally different from both the
old one and values stated in the manual.
It does not out out any current either. I'm confused!
But the engine runs much better with the new sensor...no more
hesitation during acceleration but I'm worried the engine is now running too rich.
Could it be that the old sensor had been replaced at some time by
a workshop, and that they've used the wrong type?
Anyone know what correct values are ? Cause the manual could be wrong, or there could have been an update/mod that is not included in the manual.
I guess a crude check is to measure the sensor voltage with cold and hot engine.
Abs max range would be 0-5V, typically about 0.5V when engine is cold, and about 3.5-4V when engine is at working temp. Will do this as soon as I can.
Measured the voltage today: 3.5V cold, and 0.5V hot. Looks OK !

2)
Intermittent loss of power while cruising, happens every few seconds.
The engine looses power for a few seconds, but it is still running...
meaning it does not drive the car forward...I can feel the play in the drive-train is taken up, then a few secs later (not moving the gas pedal at all) the engine gets the power back and again takes up the play in the drive-train. This causes a subtle but still very annoying 'clunk' or 'jolt'.
Tried turning off the ignition for comparison and obviously causing a total loss of power and this causes a much more severe jolt.
So its clearly not ignition related. The ignition system in this car
is a self contained system and not under the control of the ECU.
This problem occurred a few months ago, and appears to be getting slightly worse for every week.

I have checked and measured:
Throttle Position Sensor (TPS)
Mass Air Flow Sensor (MAFS)
Auxiliary Air Valve (AAV)
Idle Air Control Valve (IAC)
Engine Coolant Temperature sensor (ECT)
Also checked acceleration valve
vacuum switch
kick down and idle switches
all relays
all hoses
Suspecting a poor running fuel pump I also measured
fuel pressure with manometer (after final filter).
Manometer was placed inside the car and monitored when hesitation occurred.

All these checks out OK, at least at the point in time when they were measured.
Still not sure about the ECT though...

Just about the only thing left to check is the wiring.
Have had problems there before;
the common wire for the injectors was broken due to metal fatigue...this was in the middle of the wiring harness that runs over the top of the engine!

But doing a full check of all the ECU related wires is a mammoth task...I dont wanna do it!

Any suggestions ?

I just found the cause of this problem:
The MAF measured OK, but a visual inspection of the internals revealed that the wiper had worn through the resistor layer on the substrate, right in the
center region where the wiper typicaly is located during normal load/cruice.



3)
The ECU is obviously not OBD2 (maybe OBD1), but is there some way to read out fault codes from this ECU?