Jeep Wrangler Forum banner

Misfire p0305 adventures

7K views 8 replies 6 participants last post by  Rudman33 
#1 ·
So I recently purchased a 2009 jk w 99k miles. Got a great deal, super clean, loaded, everything I was looking for. Then it happened. At 101k it started misfiring and running like crap. All of the sudden, no warning and gave code p0305.
I changed plugs, wires, and coil pack, because they looked to be original. No change. Swapped out the crank position sensor. Still no change.
I decided to stop throwing parts at it and let a real as l mechanic check it out. 0 compression on #5. He pulled the valve cover off to see if it was a broken lifter/ push rod but everything was moving fine on turn over.
The dealer I bought it from is going to repair it. Waiting for them to let me know if it’s the head or bottom end. Any ideas???
 
#2 ·
I have a 2013 Wrangler JK, last week, at 87K, it threw Code P0305. Started running rough at idle. Bought it dealer, after they tore it apart, they confirmed a bad head. They said new head is on back-order and could take months. They put jeep back together and said I could drive it. My MOPAR extended warranty only covers 5 days of rental. Issue I have now is it is running even rougher, I smell gasoline when I drive, I get bad gas mileage and now backfires. I have read that driving with this much gasoline pass-through will kill my catalytic convertor. Yet I am stuck as they wont provide a rental car and cant fix the vehicle, I am trapped! Can't believe there cant be an exception for an extended rental car when waiting for parts and driving the Jeep causes further damage. I have an unusable vehicle and have to share a car, get rides to work, etc..



Good luck in your scenario. Sharing so you are prepared.
 
#3 ·
Hi SpottyJ,
I am equally concerned as you about your situation. Please send me a private message with your VIN# so that I can look into this further for you.

Kathryn
JeepCares
 
#4 ·
P0305 will not go away....

I have similar situation....

2007 Jeep Wrangler Rubicon
Code 0305
Changed all spark plugs
Changed coil pack
Changed spark plug wires.. code still there.. so took to Collins Brothers Jeeps.
They charged me $695 for the following only to have light go back on right after I picked it up.
Compression test (cyls between 140 and 150)
Removed upper intake manifold
Replaced #5 injector
Removed lower intake manifold and replaced gasket coolant and vacuum (leaking)
Replaced EGR tube gasket (leaking)
Installed missing throttle body bolt..

Took back to them again... they did the following for $990 and P0305 code still not going away...

Removed and checked new coil pack
Removed and checked #5 spark plug and wire
Compression test... (all cyls good)
Replaced EGR valve leaking
Removed right valve cover and check valve train (no problems found and motor is clean)
Remove ECM and send out to be checked
Repair and flash ECM
Check all wiring and connections under hood
Replace female side of engine harness to injectors.

At this point they pulled it to the side. They said they tried everything and the next step would be to open up the motor and look for internal motor problems. They asked me if I wanted them to work on it any more.
They said it may be a few month before they could get back to it. They had too many other Jeeps to work on. They would have to open up the motor and check inside. Cost could range from $2500 to $6500 more. They said there was a possibility the motor would need to be replaced.

I paid them the $990 and took home and did the following.

I replaced all 4 oxygen sensors.
Replaced Cam sensor
Replaced Crank sensor
replaced MAF or MAP sensor... I can’t remember the name.
Replaced the air intake sensor...

Still getting the P0305 code...

At a total loss...

The Jeep seem to run fine. It it does not hesitate or lose power. At idle it sounds a little rough but it has always sounded that way. We bought it used 3 or 4 years ago.

I purchased an OB2 scan tool. I can clear the code but it comes back.

Turn on the motor let it idle for approximately 81 seconds and it throws the code on the scan tool every time.

Not sure what else to try.

Might just need to take to another mechanic.
 
#5 ·
One other detail.
The code seems to just trigger at idle.

If I clear the code and don’t allow the Jeep to set and idle the code will not trigger.

I can drive it all day with no code as long as I don’t set in one place.

It triggers the P0305 code every time when setting parked at approximately 81 seconds from time engine is started.

There is something it does not like when it sets there idling and it is always about 81 seconds from when engine starts.
 
#9 ·
hi, is anybody figure it out yet? I have the same issue, runs rough on idle and p0305. One shop told me that I have to swap the engine but I don't have that amount of money right now.

I change spark plugs, injector and coil so far and the compression is within range

Thanks
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top