Temperature gauge problem?

Hi everyone,

New to this and desperate help needed please. I have owned a 1.4mpi (AQW engine) from new, now with 55,000 miles on the clock and well looked after.

About 12 months ago the temperature sender went and was replaced. As a precaution I bought a code reader/eraser. Shortly afterwards the fault code 17549 appeared, followed if not cleared by 16556. I then bought a VAG workshop manual and replaced the MAP sensor, inlet manifold gaskets fuel pump relay, fuel filter, air filter and checked the charcoal filter solenoid off the car, it's O.K. As a precaution I replaced the temp sender again with another new one.

The engine is running perfectly, plug colour is tan, 42 to 44mpg but gives the impression sometimes at traffic lights that it is running on choke for a couple of seconds. The car runs like a dream.

I then took it to the local garage to be scanned, another hidden fault showed up, 01598 and they said the battery voltage was 11.5 volts so I replaced a perfect battery with a new one. They also checked emissions, perfect, if anything slightly lean, until it gives the impression of running on choke, then the screen went red for a second and returned immediately to normal.

After recently swopping temp sensors around again I sat and warmed the car to normal operating temperature, the second the temp gauge hit normal the engine shuddered and tried to stall. Tried the other temp sender, the same happened.

Any thoughts greatly appreciated before I go mad and scrap a perfect car.

Thanks,

Steve