Why 2001 navigator have engine problems after changing 7 ignition coils and spark plugs.
5.4 intech motor.Why does a 2001 navigator have engine problems after changing 7 ignition coils and spark plugs. in the motor.. The diagnostic read that only #6 was misfiring. I could not access #8 because the e.g.r. pipe was directly in the way. Still sputtering and losing power going uphill. Need suggestions please