I keep throwing the P0300 code. It states random misfire and it is just that...random. The check engine light comes on but will go off after a few drives. The Jeep will stumble a little when taking off after initial start up but goes away after a minute of driving. If I let the Jeep warm up for a minute or two I don't get any stumble. Right now the check engine is off but I am sure I will get another random misfire in the next day or two. Any thoughts?

 

From Google:
A code P0300 may mean that one or more of the following has happened:
Faulty spark plugs or wires Faulty coil (pack) Faulty oxygen sensor(s)
Faulty fuel injector(s)
Burned exhaust valve Faulty catalytic converter(s) Stuck/blocked EGR valve / passages
Faulty camshaft position sensor
Defective computer

Possible Solutions:
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back. If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs , spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors. Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

Hope that helps

 

Check Faulty camshaft position sensor first as well as your Coil.

 

Had that for a while. Finally took it in and they found plugged cats.

 

I should mention that I have the Ripp headers with cats. I hope its not the cats, but I will start with the wiring, plugs and EGR and see what happens.

I did install new plugs and live wires when I did the headers too. Will check them and the cam position sensor.

 

I think i went too long with cracked exhaust mild. p0300. threw everything at it. EGR, cam position sensor, plugs and wires. black tape over engine light. finally took it in. they changed the ecm, then put on new cats under warranty, whew.
no problems that was 50k miles ago

 

plugged cats. If it’s multiple misfire look for the following
1. Injector fuel leaks. Could be faulty injectors or o rings around injectors. For the price just replace injectors.
2. Antifreeze leak on manifold ( especially rear) if there is then replace intake manifold lower and upper gaskets. Make sure to clean the upper and lower intake with 3 cans brake cleaner when removed since they build up a lot of residue.
3. Vacuum leaks. Ensure all hoses are secure
4 spark plugs and wires
5. Coil pack may need replaced
6. Check fuel pressure if you can ( clogged fuel filter which is internal with fuel pump. Tank easy to drop. 60 bucks amazon for fuel pump
7.stuck egr. Passenger side behind the wheel well covers. One bolt is a pain to get back on but it’s a manageable do it yourself job.

I’ve ran into just about every code and have replaced every single part I think besides engine rods and pistons and heads on this jeep. No joke. So when I see a p0300. First bet is clogged cats. Aftermarket exhaust is cheaper via eBay ( 100 bucks). Cross member and front driveline removal is necessary. Make sure to support transfer case during the cross member removal and the job isn’t terrible. Where the exhaust meets and clamps on driver side midway down the jeep you can swing a sludge at the hanger a bunch of times and where the old exhaust elbows to get it to get loose. I have a lift, so when installing it I used the lift to jack up the exhaust to the manifold while I had another person guide with a crow bar the exhaust into the upper flange. Kinda tricky. But use a floor jack while you have another friend or son help guide and wedge the upper exhaust back in. By the exhaust kits that come with clamps cause where the new exhaust elbows they’re no longer one solid piece and welded. You can weld it or clamp it yourself.