2004 Jeep Grand Cherokee (63,000 mi - V8) Check engine light indicates #1 cylinder misfiring. Spent $$ getting system flushed for carbon residue. Drove 3 weeks, started up, ran rough, and light came on again. Did more indepth $$$ flush, drove 4 highway hours, parked overnight, started up, ran very rough and light came on again. Shop wants to rip the head off etc for $1,200 more. Any ideas?

Hi Amanda , I want to help you with your question, but I need more information from you. Can you please add details in the comment box?
USA car or NOT? USA is WJ jeep gas engines.
sensor B2S1 is bad. or worse.
or wires to it burned up , clamps bad and wires hit red hot
exhaust pipe
no engine told 4.0L i6 or 4.7L v8
must be v8. bank 2.

the front sensor is bad (aka upstream)
bank 2 is not cylinder 1 bank.
on USA car , bank2, seated in driver side
is right bank of engine is 2.
facing said engine is left bank.2.
the sensor is here

in the USA there are 2 v8 smog parts, CALF or FED

seen here clearly in the service manual oem I have in hand



the 4.0 liter is very trick this year,
it has an odd splite exh manifold
but only seen on calif engines,
see next photo for 4.0L engine,

Misfires are usually caused by a problem with getting a spark to the spark plugs or an issue with the fuel supply to the injectors on those cylinders. Which cylinders are getting the misfires? This will help find the reason for the misfire. Use the comment button below with more information and I'll try to help you more.

Check the water to see it there's oil in it ...and...check the oil to see if it has water in it or if it's higher on the dipstick or not.

Sounds like a blown head gasket or cylinder rings.

Depend what Engine Model you have:
2001 - 2004 (WG) Grand Cherokee (International Markets)
1999 - 2004 (WJ) Grand Cherokee (All Markets)
WJ engine Specifications
4.0L I-6 1-5-3-6-2-4
4.7L V8 1-8-4-3-6-5-7-2
4.7L V8 HO 1-8-4-3-6-5-7-2

1999 Jeep Cherokee 4WD 4.0 liter L6 VIN "S"



Hope this helps (remember rated this).

P0301 is #1 cylinder misfire detected and is most likely related to a worn spark plug that is need of replacement. All plugs should be replaced if replacing one. Not sure how many miles you have on this vehicle, or if plugs were ever installed, but this is the basic step to take in diagnosis.

For the 1998 Jeep Grand Cherokee Laredo:
I do not know if you have the 4.0L In-Line 6-Cylinder, the 5.2L V8, or the 5.9L V8; however I have included ALL below:

For the 4.0L In-Line 6-Cylinder:
Firing Order:
1-5-3-6-2-4
Cylinders:
(back)
...6
...5
...4
...3
...2
...1
(front)

Distributor:
....(back)
.....5....3..(+)-screw
1.............6
(+).4....2

For the 5.2L V8: AND 5.9L V8:
Firing Order:
1-8-4-3-6-5-7-2
Cylinders:
.......(back).......
|..8..|.........|..7..|
|..6..|.........|..5..|
|..4..|.........|..3..|
|..2..|.........|..1..|
.......(front)
Distributor:
.....(back)
.......3
..4.........6
8.............5
..1.........7
.......2
......(front)

Let me know if this helped, or if you have additional information or questions. Feel Free to contact me at FixYa.com!

For the 1997 Jeep Grand Cherokee:
I do not know if you have the 4.0L In-Line 6-Cylinder or the 5.2L V8, however I have included both below:

For the 4.0L In-Line 6-Cylinder:
Firing Order:
1-5-3-6-2-4
Cylinders:
(back)
...6
...5
...4
...3
...2
...1
(front)

Distributor:
....(back)
.....5....3..(+)-screw
1.............6
(+).4....2

For the 5.2L V8: (Side Note 5.9L V8 = Same)
Firing Order:
1-8-4-3-6-5-7-2
Cylinders:
.......(back).......
|..8..|.........|..7..|
|..6..|.........|..5..|
|..4..|.........|..3..|
|..2..|.........|..1..|
.......(front)
Distributor:
.....(back)
.........3
....4........6..(+)-rounded tab screw
8................5
[ ].1.........7
.........2
......(front)

Let me know if this helped, or if you have additional information or questions. Feel Free to contact me at FixYa.com!

HAVE YOU REPLACED THAT PLUG AND PLUG WIRE,FIND NO3 CYLINDER AND PULL THAT WIRE OFF SEE IF ILDE OF ENGINE CHANGES IF NO THEN YOU MAY HAVE BIGGER PROBLEM BUT DEFINITELY CHECK FOR SPARK WITH WIRE ON PLUG ITSELF.

p0306 is a #6 cylinder misfire trouble code..have seen a faulty injector on 6 cyl model,plug and/or coil on v8 models