Intermittent problem could be humidity related. As mentioned above...a cracked/leaking dist. cap, or bad plug wires will cause misfiring due to shorting from humidity...work ok on a clear dry day, and be a bear when things become damp.
Also
Verify engine temp sensor...little one with two vaccuum lines located at the front of the head above and to the left (looking from the front of the engine compartment)...the sensors go bad regularily (plastic body can break free from the brass housing causing air leakage, or the vacuum lines get cracked netting a bad temp signal). This is the sensor that tells the ezl/cpu what temp range your engine is running in, and can definitely affect timing and fuel feed.
Check also that your crank sensor is not loose or does not have a damaged/broken wire.
Would check these things out before ever touching the lambda adjustment....if you do want to play with it...make sure it's only done with diagnostics, and with someone who knows what they are doign around. Using a digiatal Volt meter, you can monitor the O2 changes, and make sure that they oscillate equally above and below .5V when under different loads, or use the diagnostic pins and a repair manual to verify voltages when running..To me the O2 method is more reliable, because certain other unrelated fault codes will cause a bad read at the diagnostic pins. Better to have someone knowledgeable around when doing this...the lambda adjustments are super sensitive and should never really be done by "ear".
Last edited by MDE3; 01-17-2010 at 08:41 AM.
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