I have a 97 wrangler in-line 6 4.0l, around 1,100 RPMS it stumbles and chokes a little. I notice it more at higher speeds. We replaced the cap, rotor, distributor, plugs, wires were new at the time, so was the ignition coil. Idle air control valve, throttle position sensor, we replaced the injector for cylinder 6 and it improved. The codes that keep coming up are, PO300 and PO306. I brought it to a shop finally and they replaced the thermostat and gasket, radiator cap and the crank sensor.They also did a compression test, results were...
1-60 at first then he used marvel mystery oil and it went up to 130
All the symptoms are gone after he did the crank sensor, the jeep runs perfect, but the check engine light just came back on for the same 2 codes- p0300 p0306. I am out of ideas