Hi,

Ordered to replace my faulty MAF sensor. Engine still is misfiring and runs far better with the sensor disconnected. Is it possible that the sensor just isn't compatible with the car?

 

What year S40 do you have?

Amazon says that this does NOT fit my 2003 S40... and that same manufacturer has one a little different that does fit. If you add your vehicle to your Amazon 'Garage' it will tell you if something fits or not, and you can also search only for parts that do fit.

 

looks like it will work for a 2000 S40 (mine) but there's a diff part number for 2003s...

 

Its a 2003 Volvo S40.

 

Apparently no good for a 2002 V40 also.
I think you have ordered the incorrect version of their product.
Go for an exchange for the correct one and see if that helps.