Apr 232014
 

I have a 2004 Chevy Cavalier 2.2 manual trans. Car started shutting off when coming to a stop and when slowing down for sharp corners. Usually starts right back up, sometimes not. When it doesn’t start right back up, wait about 5-10 minutes then it will start. Idles extremely rough. Check engine light on from time to time since it started shutting off. Car has been to 3 garages, including a dealership. Checked by 4 different computers. Changed plugs, coil pack, ignition control module, map sensor, throttle position sensor, upstream O2 sensor, ECM changed, Air box changed. Had fuel pressure test done, and also had the catalytic converter checked. The more its driven, the more it shuts off. Suggestions? Is the crank sensor a possibility?

  5 Responses to “2004 Chevy Cavalier”

  1. Would love to know what the codes are, if you could post them below in the comments we will figure this one out.

    Most common cause for this would be a clogged EGR.
    possible Failed IAC – Idle Air Control or vacuum leak.

    Since it gets worse as the engine temperature gets warmer, could be a ECT.

    The codes should help narrow the issue down…

  2. The code being thrown is P0174 Bank 1 Sensor 1, System too Rich.
    I have already changed the upstream O2 sensor.
    Motor does not have EGR, it has EVAP system.

    Already changed ECT.

    Checked air being pulled into Throttle Body, not pulling as much air as it should.

  3. Also, the ignition control module hasn’t been changed like I stated. I thought it was, but was informed that it wasn’t.

  4. The ignition control module would have been one of the first things i would have tried as it generally works ok until it warms up and breaks down under heat.

    Didn’t mention it because you said you had already replaced it…. Might be worth looking into. However I would fix the Check Engine light codes first.
    ———————————————————-
    P0174 Chevrolet – Fuel Trim System Lean Bank 2

    Possible causes
    – Intake air leaks
    – Faulty front heated oxygen sensor
    – Ignition misfiring
    – Faulty fuel injectors
    – Exhaust gas leaks
    – Incorrect fuel pressure
    – Lack of fuel
    – Faulty Mass Air Flow (MAF) sensor
    – Incorrect Positive Crankcase Ventilation (PCV) hose connection

    If the P0171 is combined with the P0174 code, it’s very likely that the problem is caused by an intake leak. If there are no intake leaks, the next step is to replaced the air filter and clean the air flow meter. If the problem persist the front oxygen (O2) sensor may need to be replaced.
    The P0174 code could also be caused may be caused by one or more of the following: debris on MAF sensor causing an incorrect reading, improper oil level, low or high fuel pressure or Engine Control Temperature (ECT) Sensor reading inaccurate.

    When is the code detected?
    – Fuel injection system does not operate properly.
    – The amount of mixture ratio compensation is too small. (The mixture ratio is too lean.)

    P0174 Chevrolet Description
    The Engine Control Module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open Loop and Closed Loop. During Open Loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During Closed Loop, the ECM adds HO2S inputs to calculate the short and long term fuel trim (FT) adjustments. If the HO2S indicates a lean condition, the fuel trim values will be above 0 percent. If the HO2S indicates a rich condition, the FT values will be below 0 percent. The short term FT values change rapidly in response to the HO2S voltage signals. The long term FT makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1.

    There is a Technical Service bulletin: TSB#03-06-04-030F

  5. The front O2 sensor was already changed, along with a new ECM.

    Cleaned IAC, idle smoothed some, but shortly. Replaced IAC and reset check engine light, idle is smooth, and light has been off since yesterday afternoon.

    Thanks for your time.

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