180 sounds right for a non turbo.. are you saying your bad cylinder is doing the same psi as the others?

I would get one of those pulse fuel injector lights to ensure the injector is firing right.. if its not the injector then it could be the connection to the injector itself.. given that you swapped the injector and it was working in the other cylinder.

They say if its not gas then it could be spark or air. So perhaps you should test the spark on the cylinder in question.

Did you do the tune up in response to this problem..or did you only suffer this problem after the tune up?

Test the spark plug in question by taking it out ..connecting it back to the lead.. putting it on the metal part of the engine block(after you take any gasoline off from removing the cylinders off)have someone turn the ignition and check for a crisp blue spark between the ignition gap and see if it works. (did you also replace the spark plug wires ? if not perhaps a swap of them again with another cylinder can isolate the problem.

Anyone else have any ideas to help?
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93 850GLT 430,000km * 94 850 300,000km * 86 240GL 360,000km