So here is the question that I can not find an answer to. I have a 95 GS eclipse. Everything was cool with the car and then my code came up for rear o2 sensor, shop replaced it and then it went on again they checked it and it was fine. Now the code trips every like 5k miles or so. It has done this like 5 times in the past 2 years. So there's the question to all you gear heads that know way more than me. I have checked with several dealerships and they can't answer the damn problem.
Thanks for ur help

 

list your mods if any n that might help figure this out

 

When it all started I had wires, cold air, and muffler, But have since taken of cold air nd it has happened once more.

 

maybe they replaced the wrong o2 sensor?

what is the exact code?

 

Code 21
Is that the rear o2 sensor?

 

its for the o2 sensor...but it doesn't specify which one.

 

The second time the code came up I had the front one replaced.

 

Try replacing the other one see what happens there.

 

Both front and rear o2 sensors were replaced, the code only shows up every 5,000 miles or so.

 

Will fuel issues cause the same thing since o2s are looking at temps and AFRs maybe lake of fuel or clean burn???? just spit balling I guess but something to think about I suppose