Hey guys,

My 2008 350z has just gone through an mot and failed on its emissions.

It’s failed on the natural idle, fast idle and second fast idle. All of these are CO failures, the lambda and HC tests were fine.

the natural idle was only 0.01 off passing so I feel like with an Italian tune up, it would probably pass there. The issue is on both the fast idle tests, I failed by 0.44 and 0.72 which seems extremely high

I’ts on 120k miles and the previous owner had the back box deleted, however this shouldn’t effect emissions right?

Could anyone point me in the right direction, I honestly haven’t a clue where to begin!

Cheers.,

 

ls the car showing any DTCs? Doing so should at least point in a direction to look.

 

just done a scan of the car and the only fault present appears to be P2A00 - guessing first port of call would be to replace the sensor and see where I’m at?

 

Yes, replace the oxygen sensor. If you have a high end scanner, it will graph operation of the oxygen sensor. If the idle still does not perform properly, take off the idle control valve and clean with Seafoam throttle body cleaner.

 

Please define "Italian tune up" for us yanks?

 

I always heard an Italian tune-up was going WOT to the redline - allegedly cleaning out built-up deposits.

That's what a certain parent would always tell me when I was a kid and we were riding around in the not-so-family-friendly Alfa Spider. I think maybe it was just an excuse...