Just did a valve job on an 09 r55 and the problems just dont seem to end. The thermostat developed a crack, and throttle body was returning a code for weak return spring. I seem to have these issues sorted out but I have a persistent misfire on #4. I have eliminated the coil, plug and injector as a possibility. Compression seems to be in line with the others. When cold its fine, but as it nears operating temperature is starts to misfire and gets worse as the temperature increases. This only happens at idle. I'm using Bavarian Tech diagnostics and it appears the spark plug firing time is dropping out whenever it misfires. Has anybody ever seen anything like this before? Is there anything else I can test?