What is check engine light code 11 and 8 on Honda Civic 2004?

When I reset the ECU code 8 will vanished but not code 11, it was stored. Engine starts and runs smoothly but after an hour of driving, the engine stalls. And everytime the engine stalls I quickly look for DTC. Again and again everytime the engine stalls the code 8 is present. And as soon as I reset the ECU, engine will start again. I search for code 8 and the description is top dead center (TDC)sensor no signal/ intermettent signal interruption. Is this the possible reason why engine stalls? And for code 11, I can't find any exact description for this code. Some people says its overheating protection.I had replace the thermo switch for fan but nothing happens(i just throw money)and I had read on one of your column about engine hesitation and stalling that some troubles can't detected by scanner. And CEL may goes off if the engine runs smoothly or if replacing a suspected bad sensor(on my case maybe it's the TDC, im not so sure) now im asking for your consideration about my engine stalling. Your answer is appreciated too much.