Just recently ive been getting a cel when my car idles too long or in heavy stop and go traffic. The weird thing is that the temp. gauge will read cold with no cel then as it sits and idles it gains heat, but still no cel. When i drive and go through the gears then, mostly when i hit vtec it then throws a cel, returns the temp gauge back to cold and the secondaries do not work, but vtec does. So, i took the car to my buddie's garage, who is like the only guy who knows what hes doing with honda's around here. He told me it was my thermostat but when we checked the code it was a code 23. Which has something to do with the solenoids. Anyone ever have this problem? Any suggestions or remedies? It only has done this a couple times, so i think im going to just get a new thermostat and vtec solenoid and see if that cures it but if you have any other suggestions lemme know.

Thanks

 

https://honda-tech.com/zerothread?id=978933

Code 23 = Knock Sensor

Order I would check:
1) Check your igintion timing, set back to stock.
2) Put some premimum fuel in (highest octane you can get). Does the problem go away.
3) Check knock sensor output (backprobe knock sensor circuit at ECU) using a ocilliscope. Fequency of output should be condtant, amplitude should change as engine RPM changes. This circuit is shielded and any noise will mess it up.

Report back with what you find.