I have a 2000 jeep grand cherokee laredo that the check engine light came on and started flashing after the plugs, coil packs and fuel injectors were all replaced. Double checked all, no cracks. All inserted correctly. All tight. Was not flashing before change.

Code reader is showing misfire on all cylinders except 7. Could the O2 sensors cause this? I don't know if they've ever been changed.

250k miles on it roughly.