Okay so I replaced the Oxygen sensor on my 89 olds ciera 3.3L but the tachometer doesn't go to zero when I shut off the engine. Did I miss a step, do I have to reset something?

i don't believe those two things are connected in any way

when the car is in operation, does the tach work properly? does the needle register the correct idle speed when you turn the engine on? if it works perfectly fine when the engine is on, then you really don't have anything to worry about.

you probably don't have an aftermarket tach, but this gives an explanation:http://procycle.autometer.com/TechFaqAnswer.aspx?qid=11


still dunno why it won't zero... bump for more input.

sorry that i'm bumping like a 2 year old thread.

this is normal. sometimes when you shut off the ignition, it does not go right to zero. it does this with my 89 ciera 3.3, in fact it says in the owners manual: The needle may not return to zero when the ignition is off. if you have your manual it's page 48. bottom of the "tachometer" paragraph.