Evap monitor failed ca smog check

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1998 Dodge Caravan 3.3 l engine, bought new, failed CA smog check this year. Put in new battery, alternator, oxygen sensor and oxygen heater sensor, oil change, oil filter, and a new air filter. The check engine light is now off and I have driven to reset the monitors except for the evap and the oxygen heater sensor monitors which are still incomplete! There are no generic codes and no OEM codes found when I ran the scan again yesterday, just the 2 incomplete monitors listed above. The engine has died a couple times while at a stop sign and the idle is also rough not smooth. It feels like the engine is misfiring but my van still runs like a new car when out for a drive, except for the idle and feeling like it might cut out once in awhile. Also had a new MAP sensor installed after which when I turn the key on to start the engine, it like whines for a few seconds and then it turns over. Any suggestions, can’t afford a new car and do love my old van.

What makes this problem better or worse?

Actually it’s pretty consistent. Might be a little better after it’s run for a while but there’s definitely a problem with the idle. I feel it vibrate or shaking as it sits idling instead of a smooth quiet idle. It will even shut off the motor after several minutes, like 10 minutes or so, but not always.

How long has your 1998 Dodge Caravan had this problem?

About 2 months

Visitor

in San Jose CA

May 12, 2020

1 Reply

Popular Answer

DaveJMon May 12, 2020

The idling concern may or may not be related to why your monitors will not set. You are best to address them. The oxygen heater sensor monitor must complete to pass a smog test; the evaporative emsisions system monitor does not have to complete if it is the last item for the system to be tested in California. Engine performance testing must be performed. If you have an air intake leak, for example, you can affect idle and also cause unwanted fuel burning which can affect your oxygen sensor operation. Everything works together, so it will be essential to perform testing. It's possible all these parts you have replaced may or may not have been needed -- and even new parts if failed or incorrect in application can create more problems than they solve. Unfortunately, there are no guesses here, testing is needed. Good luck.

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