Mechanic put on a fi 2000r, tuner. I wanted bigger o2 senders, I heard they'd help.
but, he said work cause a check engine light problem.
any help?

 

If the system is set up to use the wide-band O2 sensors (18mm thread vs 12mm thread for the narrow-band), then you should be OK to convert to them. The factory narrow-band O2 sensors adjust for idle, and low load conditions, and high load and full throttle is controlled by hard programming.

 

Congrats on first post.......

 

Great first post. Get a new mechanic, that cobra sux.

 

Welcome to the forum.