P0303….At the end of my patience and wallet

bubbad323

Member
Gonna try and not make this a rant session, as frustrated as I am. Moreso hoping to hear from others who have had this code and what worked for them.

My trouble started with traction control light coming on and keep going into limp mode. Several codes were thrown and I decided to take her to the dealer thinking maybe I screwed something up when I replaced rocker arms on the passenger side of the vehicle. I also had ticking on the driver side and figured let them go in and repair the drivers side and get this thing finished. They replaced two cam shafts and rocker arms and all was great.

Few days later I get the error code. Long story short, I replaced the camshaft position sensor myself with an aftermarket and suspected maybe that was the issue. Dealer threw in a molar one and said the aftermarkets are hit or miss. Great. Sensor in and no code for about a month. Code came back yesterday. I’ve already thrown a lot of money at this thing and can’t do it anymore. I’ve done a lot of research and seems the P0303 is a rabbit hole of possible causes.

Whats confusing is that other than the check engine going on, there’s no issue with the engine or acceleration etc etc. She’s running great. I cleared the code yesterday and it’s back today. Also it seems to only trip the check engine light when I’m parked with the engine running. Not sure if that’s important to the troubleshooting.

I’m just at the end of my patience and financial ability to try and fix this thing. I’ve always taken care of this jeep. Oil changes at 4K miles and all maintenance. I don’t beat on it. It’s running great except for this code not going away. Maybe it’s a bad fuel injector? But there’s no engine issues that would lead me to believe that’s the case.

I did a tuneup last summer and the clip for the coil pack for cylinder three snapped off. The connection still seats nicely but I’m wondering if that could be a cause? At this point I’m at a loss. Dealer said could be electrical but I don’t have the money to have them diagnose and go in a wild good chase. If anyone has gone through this nightmare and can share any advice that I could do myself I would appreciate it. Really don’t want to let her go but I may have to. It’s a 2014 with 129k and very well maintained.
 
Gremlins like these suck . There’s always a sure fix put some black tape over the check engine light and drive it like you stole it.
Option two they have been known to catch fire .
 
I would check your coil pack for cyl 3, especially if you broke the clip. If it isn’t making a solid connection that could cause your misfire code for cyl 3 only.
Thanks. Trying that next. I will replace the clip. I think Autozone has them. Not sure it has to be Mopar but a new clip that clicks on is in order. I just saw a video on how to test the coil pack with a voltage pen. Giving that a go also. Becusee I have no acceleration issues etc I don’t think it’s the fuel injector.
 
This would be my guess. Might seem like it’s seated and tight but probably isn’t.
My plan is to change the clip. If that’s not it I, I will change the spark plug and also swap the coil pack for cylinder 1 and see if I get a code on that cylinder. If so then I’ll replace the coil pack. What a pain in the ass. 🙄
 
Update: hooked up my scanner and ran the live data for the misfires. Took a drive. No misfires when driving. Only when stopping and idling or when slowing down. Very strange. Zero misfires on the highway and I drive about 30 miles. Anyone have any ideas based on this? I also checked some live data on fuel injectors. Number 3 injector numbers seemed to be in line with the others so I don’t think this is an injector issue.
 
I'm almost wondering if you have some carbon around the valves/seats. Sure is strange it only occurs at idle.
 
Update: hooked up my scanner and ran the live data for the misfires. Took a drive. No misfires when driving. Only when stopping and idling or when slowing down. Very strange. Zero misfires on the highway and I drive about 30 miles. Anyone have any ideas based on this? I also checked some live data on fuel injectors. Number 3 injector numbers seemed to be in line with the others so I don’t think this is an injector issue.
Under a load you’re producing more current thru the coil to light off the plug. It’s able to jump the gap easier than at idle. A burnt terminal in that coil connection could be the cause of the weak spark while at idle. Check your broken connector
 
going to tackle the connector tomorrow or early during the week and see if this fixes the issue. Thanks all for the feedback and help. Fingers crossed this is the problem. Driving me bat shit
 
Have a leak down test done. My engine had two bad valves and a bad head. If I’d started with a leak down check, I would have save a few hundred dollars.
 
Have a leak down test done. My engine had two bad valves and a bad head. If I’d started with a leak down check, I would have save a few hundred dollars.
Thanks. Sounds expensive and im tapped out sending this thing to the shop. If the clip, plug and new coil pack don’t solve this then I’m looking for a new vehicle.
 
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