Odd High Rev Problem

[Elijah]

So I drive a 1991 MR2 SW21 with a 3SGTE swap and full turbo swap as well with a 94 ECU and full turbo axles. Anyway the problem is this, After about 20 minutes of driving the idle goes from 1100 to 2200, then another 10 mins or so and the idle jumps to 3100, then another 10 mins and the idle spiked to 4200 and I shut the car off for fear of it rising all the way to redline. After the RPM's jump such a high amount the turbo timer stops functioning and no longer lets the car wait the 5 minute idle just does an instant drop off.

Is this a problem anyone else has had or even heard of? After the idle kicks up the throttle line becomes loose and full of slop until you rise above the current RPM. The throttle itself on the engine is not stuck and the gas pedal likewise does not stick. Im at my wits end and am not paying 350 USD to have a shop run a diagnostic on a modified car or paying the 120 USD to have a custom low clearance tow truck capable of towing a 3 inch clearance car to the shop.

Elijah~