Has anyone experienced improvement on gas mileage on their car after replacing the upper oxygen sensor and ignition coils? Before the replacement when I see 2 lines on the gas gauge the car spins around 500km now after replacement I get around 590km. Wife is the one driving the car and she uses it as her daily and the gps is showing same route and average speed on every trip.

 

Hello,

I have a 2009 S with 140K miles and, "yes", I noticed a increase (actually, a return to normal good mpg) when I replaced spark plugs, coils, and both O2 sensors.

W

 

Replacing the O2 sensor, spark plugs, and coils will make the burn much more efficient, which leads to better fuel mileage. Shouldn't be much of a surprise, but rather emphasizes the need for regular maintenance on those items.

 

How often would O2 sensors need to be replaced?

 

The O2 sensors should only need replacement when they start to give OBD faults.

 

That's how I have worked it on all of my other vehicles. Reading it here it seemed they were being changed for no error reason....thanks!

 

How about spark plugs and coils? Whats the good change interval? Should the coil be replaced when it acts up?

 

For my non-s R56, I see wear on coils and plugs around 40K miles

 

What should I look for to see coil wear? Traces of arcing?