Hi all, I'm in dire need of help/a sanity check...

Currently I have a 1990 gt and I am ready to pull my hair out. About 6 months ago I was driving normally when the CEL light engaged. Upon completing a diagnostic test, it threw up error codes 35 (turbo pressure sensor) and 52 (knock sensor).

Since this time, I have tried everything i can think of to solve these problems. I've replaced the knock and turbo pressure sensors with brand new units, I've had an auto electrician test the power to both sensors from both sides, I've replaced the ecu and used a timing light to confirm the knock sensor is indeed doing its job. Rather interestingly the cel light does not come on at start up, but only when 1700 rpm is reached.

To add to my frustration, The car runs great but is not being driven until i sort these problems out. Has anyone experienced anything like this or have any idea's??

If you've replaced both sensors and also the ecu then it must have to be a fault in the engine wiring loom?
Have you or your auto elec performed the tests suggested in the workshop manual for the car? Big green book.
It explains in great detail how to test individual components etc.

I assume you've cleared the codes from memory after you replaced the sensors?
The engine will run fine without the boost sensor by the way. It just provides a reading to the ecu for boost cut and also to operate the boost gauge in the cluster.