Code PO206 and PO306 - 2006 Jeep Wrangler 4.0

PO300 and P1399 are random cylinder misfire detected.
PO301 cylinder 1 misfire
PO302 cylinder 2 misfire
PO304 cylinder 4 misfire
PO306 cylinder 6 misfire
I would say that you have damage to the ignition wiring harness or you ECM is failing.

To start with, I would unplug one of the other injectors and measure its resistance with an ohm meter to find out what normal is. Then measure the injector's resistance for cylinder 6. If it reads open circuit, shorted, or significantly different than the others, it must be replaced.

If both injectors measure exactly the same, the problem is either in the wiring or the engine computer. The diagnosis gets a little more involved then. It involves disconnecting the engine computer's connector and measuring the injector's resistance between the two wires in the connector.

Based on the uncharacteristically low failure rate of Chrysler injectors and engine computers, you might look for a more simple cause. In particular, a corroded pin in an electrical connector comes to mind. Try wiggling the wiring harnesses on the engine and near the engine computer while the engine is idling. Based on the age and mileage, it is also possible for a wire to be rubbed through where is slides across the body due to normal engine movement

Replace the fuel injector on cylinder 6.

code po306 means cylinder number 6 misfire detected, possible causes air leak in the intake manifold or in the egr or pcm system, could have mechanical problem number 6 cylinder like burned or worn valves,could have clogged fuel injector or faulty fuel injector,could have bad ignition coil, bad spark plug or bad spark plug wire.

po206 is the is the inj. 6 not responding to control signal.
po306 is a misfire in the no.6 cylinder..
Check your ignition leads or the coils.
Ummm the spark plug.
It's a bit hard over the net but I hope this helps you

Sounds like you still have air leak.

the bottom crank pulley is either lose! the keyway sheared and vibrateing against the crank sensor or the bolt in the crank pulley has backed off or fell out

P0301 = Cyl no 1
P0306 = Cyl no 6

If you have changed plugs and leads and confident that they are now ok you need to run a compression check on all the cylinders, I'd emagine they should all be running at approximately 150psi per bore, if 1 & 6 are down it could be the head gasket, timing or piston rings.

Plug, plug wire, plugged or open fuel injector. are the most likely.

i would check wiring at injector 6 for a bad contact if ok test injector