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-   -   2006 4.7 P0300 Multiple Cylinder Misfire (http://www.jeepgarage.org/f181/2006-4-7-p0300-multiple-cylinder-misfire-47533.html)

SvenskaJeepGuy 09-16-2012 12:54 PM

2006 4.7 P0300 Multiple Cylinder Misfire
 
backround..... changed the plugs with oem champions around 5k miles ago, drove to and from florida recently with no reported ploblems.

last night i was driving home from nyc and while going through the pocono mtns my jeep was having problems on the up hills. at 65mph it would start to have a knocking sound and then shake like on rumble strips. i would lose a bit of power and the check engine light would quickly flash. i would coast down to around 55 and then it would allow me to go back up to 65 until the next up hill area and it would do the same thing again. eventually tried the hills at 55 and the same thing would happen. the jeep was fine at level ground, did 80 easily to pass a bus, but could not handle hills. the key dance brought up no codes but when i got home, my tuner showed me P0300 multiple cylinder misfires. anyone have any ideas? i dont want to start replacing a chain of parts that are going to cost me a ton of time and money. it needs to go to the dealer soon for scheduled transmission fluid and filter service but i am trying to save on their charges:thumbsup: thanks!

Scottina06 09-16-2012 02:24 PM

Re: 2006 4.7 P0300 Multiple Cylinder Misfire
 
P0300 possible causes:

INTERMITTENT MISFIRE
VISUAL INSPECTION
IGNITION WIRE
(F42) ASD RELAY OUPUT CIRCUIT
ENGINE MECHANICAL PROBLEM
IGNITION COIL
COIL CONTROL CIRCUIT
SPARK PLUG
CHECKING FUEL PRESSURE
FUEL PUMP INLET STRAINER PLUGGED
RESTRICTED FUEL SUPPLY LINE
FUEL PUMP MODULE
CHECKING FUEL LEAK DOWN
FUEL INJECTOR
INJECTOR CONTROL CIRCUIT
PCM

NOTE: Anything that affects the speed of the crankshaft can cause a misfire DTC.

NOTE: When a Misfire is detected for a particular cylinder, the PCM will shut
down that cylinders Injector Control circuit.

Visually inspect the engine for any of the following conditions:

- Worn serpentine belt
- Binding Engine-Driven accessories: A/C Compressor, P/S Pump, Water pump.
- Misalignment Water pump, P/S Pump and A/C Compressor pulleys
- Corroded PCM power and ground circuits.
- Improper CKP, CMP, MAP, and TP Sensor mounting
- Poor connector/terminal to component connection. i.e., CKP sensor, Fuel Injector, Ign coil, etc.
- Vacuum leaks
- Restricted Air Induction system or Exhaust system.

Madanio24 09-16-2012 03:03 PM

Re: 2006 4.7 P0300 Multiple Cylinder Misfire
 
When the check engine flashes it means the misfire is currently happening. Check all connections


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