99 Explorer code question?
P0306
P0171
P0174
Any insight that can be provided would be very much appreciated.
Thanks
306 = cylinder #6 misfire
171 = system lean, bank 1
174 = system lean, bank 2
Try changing the plug/wire on #6 (driver's side rear) to clear the PO306
The 171 and 174 are probably related, and are usually caused by a vacuum leak or dirty MAF sensor. You could have a leaking intake manifold gasket(s) causing the vacuum leak, very common on the 4.0. Try re-torquing the intake bolts first, see if that helps. If not, you may have to replace the O-ring gaskets.



