P0303 error code for 2012 liberty

I just bought a used 2012 liberty 4x4 v6 for my son, it has 92K miles on it and got this code yesterday we have only had it for 2 days P0303 P0300. engine misfire.
What are primary causes and fixes and approximate cost to repair?

 

Welcome @Jeepsport75 ...that's an unfortunate occurrence. Any chance for the selling agent to handle the problem. A P0300 code indicates a random/multiple misfire has been detected. The PO303 points at cylinder #3 having an issue. The P0300 could result with worn spark plugs/wire@90k, ignition coil, etc. If you cannot handle the repair yourself get an estimate from a shop you can trust or the dealer.

 

I called the dealer back, he is going to look at it today, for me thinks it is spark plugs, but i am trying to educate myself so when i interact with him i can ask the right questions, would a smaller battery in the vehicle cause this error code?

 

How small of a battery? How do you know that the battery is not to spec?

 

it only takes up about 3/4ths the battery tray?

 

Like some things in life size is not the only criteria. How it performs is more important. As long as it meets the CCA specs or better for your vehicle that won't be an issue.

 

Where would you find the specs? dealer said he replaced the ignition coil pack? said he drove it and it was fine.. we will see i am picking it up today

 

Check the sticker on your battery CCA rating. Between 650-800 CCA and you should be fine. Take note of the date too.

 

So he replaced #3 ignition coil pack and new plugs and wires cleared code and it drove for 24 hours then popped a P0300 random misfire code today, he asked if I was using premium fuel? Would that be the issue if I was only using 87 octane?

 

Review the Jeep owners manual about for the fuel octane recommendations. I doubt premium gas is required or necessary for that engine.

 

I didn’t think so either but I will check it out
Thanks for all the help