I put a new head gasket on a few months ago, and the car was running fine (new belts and valves in head too). Then I had some problems with the idle being too high or too low at random times.
Now i have 2 engine codes which set constantly 113 and 143, throttle switch and injectors. The car is running poorly. It will stall after startup unless you hold open the throttle a bit. It surges when you lift off the gas, opening the throttle too fast will make it stumble to the point of stopping.
The O2 sensor reads 0.75, which is too rich I think, and the gas mileage is poor.

So I checked the fuel pressure and it was 2-3 pounds too high, replaced the FPR and rechecked pressure and its OK.
The throttle switch is OK. Grounded with throttle closed, open off idle.
Ran the diagnostic for the fuel system. It operated the Air bypass, injectors and
cannister solenoids OK
Pulled the plugs and they are sooty, from too rich I guess.
Checked the engine temp sensor and it's in range at the 30 deg temperature we had then.
Anyone recognize these symptoms?

I don;t think this car has a cold start injector.
Ideas welcome.
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89 744&745-16v's 4+OD, 91 245SE auto, 84 242 Ti 4+OD