CRAZY!? - Bouncing Tach and Loss of Power
 

After 3 weeks of patiently waiting for the Honda dealer to fix my 2002 Civic LX - I decided it was time to take matters into my own hands! Hopefully the experts on this forum can help me out??

Issue: It seems that on warm/hot days, while driving, the tach will intermittently drop to zero, and my check engine light will flash on, but then regulate itself and go back to normal. It is a super quick drop of the tach and quick loss of engine power. When/if this continues for half a dozen times within a few miles, the tach will eventually drop and stay at 0rpms, the temp gauge will drop to cold, and the check engine light will stay on. The last time this happened it seemed like the automatic transmission locked itself in a high gear? It was slow going as I tried to accelerate from a dead stop. If I pull over, and restart the car, it will act like there was never a problem!

No codes are being shown at all, so mechanics haven't really been able to help me since it's intermittent. I have seen similar posts but I have not seen the solution.

PLEASE HELP! I need my car back!! Thanks.

Sounds electrical. There's no way the temp gauge will drop cold while running. I'd check the car's ECU. Swap it with a known working one and see how that goes.

Sensors
 

This sounds like a real tach problem. That is, the sensor that reads rpm really isn't working. Without it the ECM cannot advance the timing therefore no power, and even shift the gears. Check the crankshaft and camshaft sensors. They do work or the car would not start. However, they are not reading the rpm as the car runs. Many times these problems do not set codes.