Full throttle switch and Head temp sensor

I have a definite loss of power and have been hunting around for possible causes. The car pulls smoothly but weakish from idle to approx. 3500rpm at which point there is a definite surge. After this the engine just seems to be trying to catch up. Two things I've noticed; the full throttle switch clicks in at about 60% of peddle movement and head temp sensor is old type with one male connector in plug not two.
Is full throttle switch supposed to come on at exactly full peddle to the metal(I mean wood) or somewhere in between. Could this have something to do with my problem?
I'm having trouble testing head temp sensor as per Bentley because of only single plug. How to do it with old style plug?
Any other suggestions?
Thanks in advance.

86 factory t-look

I posted late. Try again. Thanks

Poorsche,

I got this some time ago from Rennlist.

Good luck! Double-check all items and p/ns mentioned. Again, I have not done this, someone from RENNLIST has passed this on to me.

Checked cylinder head temperature sensor
(temperature sensor II)
Test procedure:
on the left side of the engine next to the fuel filter
locate the bracket
with three connectors, disconnect the upper plug, on
the fixed half of the
connector (not the cable) measure the following:
resistance sensor-output - ground is in a range of
4.4-6.8 kOhms
(@ 0 degrees celcius)

0' Celcius 4,4 - 6,8 kOhms
15-33'C 1,4 - 3,6 kOhms
40'C 1,0 - 1,3 kOhms
100'C 160 - 210 Ohms
130'C 90 Ohms

(my reading was 4.8kOhms, but I will replace the
sensor anyway because it's
the old style with no seperate ground wire)

Part number for 2-wire upgrade part:
930.606.915.00 (was not available from BOSCH only from
PORSCHE)
Order sensor for 84-89 Carrera! You will automatically
get the updated
2-wire part.

If You order the sensor for 964 You will most likely
receive the following
part:
993.606.013.00 = BOSCH 0 280 130 097 => YOU CAN NOT
USE THAT! (It has a
different electrical connector, shorter wire & larger
sensor diameter)
Guess where I know this from...

Did cap,rotor,spark plugs,fuel filter,removed air flow meter and cleaned internals seemed same. Changed O2 sensor which made a difference. Seems to be more eager to rev; Until about, actually exactly, 3600rpm . At which time the engine seems to loose power. It will rev to redline smoothly but reluctantly. Almost like it not getting enough fuel.
The air flow meter has access to it's adjusting allen screw (drilled out by PO). They've also opened the black plastic cover on the bottom of air flow meter and just siliconed it shut. Therefore maybe wrong adjustment of air flow meter? Can I do this without gas analyzer.
I read something on previous post about reading O2 sensor voltage while adjusting 3mm allen screw.

My first porsche but I thought the fun was supposed to start at 3600rpm.!?