How many 02 sensors are on an 89 Chevy 454 dually?


Asked by Aug 16, 2014 at 06:32 PM about the 1989 Chevrolet C/K 3500

Question type: Maintenance & Repair

My emissions on the high rpm test were too
high and I was told it was probably the 02
sensor or the cat. The cat is only a year old
and the rebuilt motor has less than 1k miles
on it so I don't think it's the cat.

7 Answers


should only be one, I would like to know what gas it was that was too high

Best Answer Mark helpful

Co% max is 1.5 my amount measured was was 2.91 on the idle test. At 2544 rpm.It passed everything else


ya, o2 sensor seems like a good place to start


Thank you very much


If not the sensor any other guesses?

1 of 1 people found this helpful.

if its not a bad sensor then something is throwing it off and its not burning clean, high fuel pressure (not likely unless you have modified it), leaky injector, timing issue, or the new cat isn't working as they should.


Thanks again.

Your Answer

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