My 2003 S-Type V6 3.0 is running in restricted performance on cold start and has open loop running rough at idle. It also has a pending and stored code P1647. Recently, I replaced the mass airflow sensor. I also noticed there is a wire running from the engine fuse box (F37) to the back of the intake manifold on the passenger side (bank 1). I've replaced the spark plugs and coils on the driver’s side, but I haven’t replaced anything on the passenger side where the F37 fuse wire is, because the intake is in the way.




FUSE

 

I don't understand - why are you ignoring the problem with the O2 sensor?

 

Agree with the above. Also, what brand of MAF sensor did you use? No name engine management parts have been known to cause no end of grief for members of these forums...

The wire may be one of the ones that connect to the tuning valve solenoids on the rear of the intake manifold, hence the issue on F37.

 

Thank you for the information I'm quite young learning as I go, I had replaced the MAF with a Hitachi but no changes. I ordered some new heated o2 sensors from amazon should be here soon, thank you for your help.

 

Again, S-types are very sensitive to engine management components. OE, or Denso (OEM) Oxygen sensors are by far the preferred choice here..

Vendor branded, or no-name/off brand units are often made in the Sum Ting Wong Parts Manufactory #27, which is located in the same town in China as the Wok Hom brand....

 

copy that.