P0300 Code: Spark Plugs, Coil Pack, or Something Else?

[Phileas Fogg]

Our 05 Rubicon has had no engine work or parts changed since we bought it 500 miles ago. It just turned 82,000 when the ✔ engine light came on, and started running rough. It shows a code P0300. Any thoughts? Part numbers? Thank You! P.S. yes it needs an oil change any recommendations? I take our car & truck to a local family owned oil change shop and it helps with more frequent changes, any real strong reason for other options? Thanks Again!!!

I had this for 1st time ever last week. Was advised here to change the plugs. I did and all fixed.

 

[Ted05Rubi]

I had this for 1st time ever last week. Was advised here to change the plugs. I did and all fixed.

Good to know!

 

[Dougswrangler07]

Thanks for the update, it's much appreciated! Glad your TJ is back to running the way it should.

Hey Chris, I have multiple code on my dashboard of my 2007 Jeep Unlimited Sahara. FYI I had to replace my engine at the end of 2020 it only had 130,000 give or take. After I pick up my the mechanic he informed me that I needed to replace my catalytic converters & quoted me for $1200. Code was not on before I had him replaced the engine. Now all this new codes came on. First was the Gascap I bought 2 locking caps that would not even lock & would turn the code off. Then it showed a small emission leak so I replaced the canister along with a park that goes on canister, sorry I can’t recall the parts name. After I replaced canister light went off only for a few days. Second code is for catalytic converters. I live in California so I found some catalytic converters that start at $1200 ouch. Third code is for multiple misfires. Here are all my codes I would definitely appreciate any advice you give me. Please help!!
Codes 8 in total.
P0457 shows twice
P0456 shows twice
P0440 shows twice
P0300
P0430

 

[Jerry Bransford]

Hey Chris, I have multiple code on my dashboard of my 2007 Jeep Unlimited Sahara. FYI I had to replace my engine at the end of 2020 it only had 130,000 give or take. After I pick up my the mechanic he informed me that I needed to replace my catalytic converters & quoted me for $1200. Code was not on before I had him replaced the engine. Now all this new codes came on. First was the Gascap I bought 2 locking caps that would not even lock & would turn the code off. Then it showed a small emission leak so I replaced the canister along with a park that goes on canister, sorry I can’t recall the parts name. After I replaced canister light went off only for a few days. Second code is for catalytic converters. I live in California so I found some catalytic converters that start at $1200 ouch. Third code is for multiple misfires. Here are all my codes I would definitely appreciate any advice you give me. Please help!!
Codes 8 in total.
P0457 shows twice
P0456 shows twice
P0440 shows twice
P0300
P0430

Multiple misfires... hmmm... might be caused by a bad crankshaft position sensor and if the JK's ignition system is like the TJ's waste spark system, the wrong spark plugs can cause misfires too. The most likely type of spark plug that can cause misfires is a single-tipped platinum plug where the platinum is only on one side of the gap. Double-tipped platinum (platinum on both sides of the gap), conventional, and iridium-tipped plugs are fine.

 

[Chris]

Hey Chris, I have multiple code on my dashboard of my 2007 Jeep Unlimited Sahara. FYI I had to replace my engine at the end of 2020 it only had 130,000 give or take. After I pick up my the mechanic he informed me that I needed to replace my catalytic converters & quoted me for $1200. Code was not on before I had him replaced the engine. Now all this new codes came on. First was the Gascap I bought 2 locking caps that would not even lock & would turn the code off. Then it showed a small emission leak so I replaced the canister along with a park that goes on canister, sorry I can’t recall the parts name. After I replaced canister light went off only for a few days. Second code is for catalytic converters. I live in California so I found some catalytic converters that start at $1200 ouch. Third code is for multiple misfires. Here are all my codes I would definitely appreciate any advice you give me. Please help!!
Codes 8 in total.
P0457 shows twice
P0456 shows twice
P0440 shows twice
P0300
P0430

A 2007 is not a TJ, that’s a JK. You’re in the wrong forum. You want this one:

https://wranglerjkforum.net

 

[RandBow]

First time caller... I have a 2001 Jeep Wrangler 4.0 straight six 4X4. For the past couplie of months I've replaced Crankshaft sensor, camshaft sensor & camshaft Synchronizer, Coil Pack, Sparkplugs, checked compression (all within limits), used fuel treatment, checked for vacuum leaks. the most recent part was the camshaft Sensor and Synchronizer, the light was reset and stayed off for about two days. The light did flicker on the first day but did not throw a code. Today it's throwing the P 0300 CODE. It's running good, I just need to bury that code and move on! Now, when changing out the sparkplugs, I found the fifth plug's Ground Electrode to be touching the Center Electrode, leaving NO gap. Unknown if this could cause further internal damage??

 

[macleanflood]

First time caller... I have a 2001 Jeep Wrangler 4.0 straight six 4X4. For the past couplie of months I've replaced Crankshaft sensor, camshaft sensor & camshaft Synchronizer, Coil Pack, Sparkplugs, checked compression (all within limits), used fuel treatment, checked for vacuum leaks. the most recent part was the camshaft Sensor and Synchronizer, the light was reset and stayed off for about two days. The light did flicker on the first day but did not throw a code. Today it's throwing the P 0300 CODE. It's running good, I just need to bury that code and move on!

What brand of sensors did you use? I went Mopar on everything to fix mine and Napa on the crankshaft since Mopar is unobtainium.

-Mac