My 2002 Honda Civic is losing power when the engine is cold. When I am drive down the road and the engine gauge reaches 3000 RPMs it lose power. Once the engine has warmed up the problem goes away.

If I leave it in the driveway it and let it idling after 1 minute it wants to stall now this continues for 5 mins and then the engine runs fine..

Any thoughts on this I have changed the spark plug and have placed a volt meter on the battery which read 14 volts while the engine is idling.

Any help would be appreciated.

JMBSI

TxGreaseMonkey

Replace the Engine Coolant Temperature (ECT) Sensor, which affects fuel injector pulse width. The ECT Sensor is a temperature dependant resistor (thermistor), whose resistance decreases as the engine coolant temperature increases. It provides a richer mixture when cold, leaner mixture when hot. They become corroded, due to not changing the coolant frequently enough, flood the engine, and waste a tremendous amount of fuel.

JMBSI

I was told that it could be the secondary CO2 sensor.

JMBSI

I was told that it could be the Secondary CO2 sensor or a relay in the timing what do you think.

TxGreaseMonkey

Did you check for codes?

JMBSI

Yes the engine light did come on however the code said high voltage secondary C02 Sensor. But then I was told the the CO2 sensor only operates when the exhaust heat up. I don't know what to think any more the more insight that is provided the less money that I invest in.

I appreciate your insight

TxGreaseMonkey

Setting a trouble code often means a sensor is reading out of range. It may read out of range because it is bad, or because some other problem is causing the engine to be out of balance (e.g., a bad ECT Sensor). A code dump alone may not pinpoint the problem.

What was the exact code? If it was P0138, I would:

. Check the wiring to the rear catalytic OXYGEN Sensor.

. Replace the ECT Sensor (cheap and easy).

. Replace the rear catalytic oxygen sensor, if the problem persists. This should be pretty straight-forward. Go with a Denso oxygen sensor--stay away from generics.

. Change coolant with a 50/50 mixture of G-05 antifreeze and distilled water.

The cause may be a bad ECT Sensor (caused by the coolant) and the effect a Code P0138. ECT Sensors become corroded by not changing the coolant frequently enough and by not using distilled water. Then, phosphate scale (insulator) develops on the ECT Sensor and causes problems.

JMBSI

Thank-you I will complete the repairs that were suggected. Once again thank-you.

TxGreaseMonkey

Here's what the ECT Sensor looks like and costs:

http://www.autozone.com/autozone/cat...ext=ect+sensor

The ECT Sensor has 2 wires going to it, while the ECT Switch has only 1. This should help you identify the proper component.

After you make the repairs, use a code reader to erase the code(s) and reset the ECM.

Spiritualquest

Will the sensor going bad always trip a code? We have 50 percent power after changing the catalytic and sensors (they really needed to be changed), but there is no code. Car works just fine, but just low power.