rennmax

Jason I'd be interested to know how to install porsche's fix and install a TPS.

JasonAndreas

The easiest way (Porsche's fix -- there are a few that have done it) would be to find a donor ECU, MAF, TPS, ISV, wiring harness, etc. from a crashed MY94-95 993. The cheapest way would be to repurpose (the pressure sensor input is not really being used) an A/D channel and mod the MY92+ ECU software. That would obviously improve your situation but there is something else here at play.

There is no protection from high cylinder head temperatures. The ECU actually clamps the sensor value at a little less than ~300F so the CHT is only referenced during warmup.

fast951

When the engine is cold the DME tends to run a richer mixture and advance the timing. Once warm the Cold Start Cycle is out of the equation.
The Fuel pressure regulator seems to be working fine on your car.
The AFM reacts the same cold or hot, this may not be the issue.

Have you checked your AFR? Are your knock sensors working fine? Is your TPS reading differently when cold vs. hot?

There are many things that make the car feel lazy. Best approach is to verify the proper operation of the various sensors before swapping parts.

NineMeister

The vacuum side of the fuel pressure regulator is used to maintain a constant pressure differential between the fuel rail and the intake manifold. At idle the manifold pressure drops and hence the manifold pressure drops the fuel pressure by the same amount. This reduction of fuel pressure at idle thus requires a longer injector pulse width to deliver the correct fuel volume per cycle - hence improving the resolution and accuracy of the fuel control.

By the sound of your problem the engine is running lean when it gets hot - one possible cause of this that others have touched on is a faulty cylinder head temperature sensor which is out of calibration once the engine is warm.