Pls Help! P0303 code keeps coming back
08-21-2024, 12:02 PM
#1
JK Newbie
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Join Date: Aug 2024
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Pls Help! P0303 code keeps coming back
Hi All,
I'm new to the boards because we are at our wits end with this stupid P0303 code (cylinder 3 misfire). 2017 Jeep Wrangler JK Unlimited, 133000 miles. I am out of extended warranty and dont know where else to turn, figured I'd ask the experts! Got the code originally in May, so replaced all the spark plugs with NGK laser iridiums, Code went away for 2 months, life was good. August comes and the lights comes back, rough idle only in park, same code, of course
, checked #3 replaced it because maybe it was a bad plug, at the same time replaced the coils as well with TRQ coils. YAY...check engine light went away again for about 3 weeks then lo and behold, "bling" check engine light again while sitting in traffic. Proceeded to replace all 6 fuel injectors and respective gaskets, running beautiful, purring for about another 2 weeks...check engine fixed! Today, check engine light comes on again, rough idle now both in park and at a stop! I'm so over this! Someone please help, what else could it be, what should we have checked? It's very worrisome since I no longer have warranty to take it in.
I'm new to the boards because we are at our wits end with this stupid P0303 code (cylinder 3 misfire). 2017 Jeep Wrangler JK Unlimited, 133000 miles. I am out of extended warranty and dont know where else to turn, figured I'd ask the experts! Got the code originally in May, so replaced all the spark plugs with NGK laser iridiums, Code went away for 2 months, life was good. August comes and the lights comes back, rough idle only in park, same code, of course
, checked #3 replaced it because maybe it was a bad plug, at the same time replaced the coils as well with TRQ coils. YAY...check engine light went away again for about 3 weeks then lo and behold, "bling" check engine light again while sitting in traffic. Proceeded to replace all 6 fuel injectors and respective gaskets, running beautiful, purring for about another 2 weeks...check engine fixed! Today, check engine light comes on again, rough idle now both in park and at a stop! I'm so over this! Someone please help, what else could it be, what should we have checked? It's very worrisome since I no longer have warranty to take it in.
08-26-2024, 10:55 AM
#3
JK Jedi
thread is moved to Stock JK Tech.
So, i know this is for P0306, but all the cylinder misfires are going to be the same. I just happen to have these pages on hand cuz posted for someone else that was having cylinder 6 issue. pages from service manual attached.
If that were my jeep, I'd be doing a compression test on cylinder 1, 3, and 5 for a good comparison. You could have a head issue, or a head gasket issue. the good news is at least you're on the passenger side there and super easy to access the plugs and do a compression test vs. the driver's side.
So, i know this is for P0306, but all the cylinder misfires are going to be the same. I just happen to have these pages on hand cuz posted for someone else that was having cylinder 6 issue. pages from service manual attached.
If that were my jeep, I'd be doing a compression test on cylinder 1, 3, and 5 for a good comparison. You could have a head issue, or a head gasket issue. the good news is at least you're on the passenger side there and super easy to access the plugs and do a compression test vs. the driver's side.