P0303 P0302 code......help

[donshaw]

I have a 2021 Rubicon Gladiator with 78k miles and I get a p0302 p0303 code when I accelerate hard. I just replaced the coil packs today and I still get the code when I accelerate hard. My next step is to replace the fuel injectors.

What is the likelihood it's a lifter issue? The Jeep has had a pretty easy life lol
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[Hootbro]

Did you do spark plugs also?

 

[ross neill]

I would run a good fuel injection cleaner with premium fuel first then new spark plugs then injector rebuild or replacement good luck

 

[Stan H]

I have a 2021 Rubicon Gladiator with 78k miles and I get a p0302 p0303 code when I accelerate hard. I just replaced the coil packs today and I still get the code when I accelerate hard. My next step is to replace the fuel injectors.

What is the likelihood it's a lifter issue? The Jeep has had a pretty easy life lol
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Faulty Spark Plug #3
Clogged or faulty Fuel Injector #3
Faulty Ignition Coil #3
Fuel Injector #3 harness is open or shorted
Fuel Injector #3 circuit poor electrical connection
Ignition Coil #3 harness is open or shorted
Ignition Coil #3 circuit poor electrical connection
Insufficient cylinder 3 compression
Incorrect fuel pressure
Intake air leak

These are the most likely possibilities and are the things I would check first.
Spark #3 bank 1 is thd second cylinder on the passenger side . Even cylinders are on the left (drivers side ) ( bank 2) cylinders 1,3,5 passenger side ..cylinders 2,4,6 (drivers side Bank 2) typing the codes in your internet browser will tell you alot .
303 or 30(3) spark plug #3 ...302 or 30(2) is sparkplug # 2
Plus it can also be Injector #3 or Injector #2
I agree with previous poster put a can of seafoam fuel additive to it . Premium gas on a full fresh tank and run the pissola out of it for a couple of days get on that thing get those rpms up to 3500-4000 accelerate more aggressively getting on the highway etc... if it doesn't clear out in a few days then look at that list and proceed. Sometimes babying an engine too much isn't the best thing for it.

 

[Jeepmonster]

I had misfire codes that started out intermittently and would clear on its own. It got more frequent over time (years). I tried fuel additives, 92 octane, etc. Turned out to be a bad head gasket. Check your coolant levels. I knew something was wrong, as coolant was disappearing. Oil analysis confirmed glycol in the oil. First dealer couldn't find anything wrong. Second dealer caught it.

 

[Stan H]

I had misfire codes that started out intermittently and would clear on its own. It got more frequent over time (years). I tried fuel additives, 92 octane, etc. Turned out to be a bad head gasket. Check your coolant levels. I knew something was wrong, as coolant was disappearing. Oil analysis confirmed glycol in the oil. First dealer couldn't find anything wrong. Second dealer caught it.

Did you loose the engine ? Or did you manage to save it.? Alot of times coolant in the oil will cause bearing damage. I am extremely curious to here the outcome of your head gasket situation.

 

[Jeepmonster]

Did you loose the engine ? Or did you manage to save it.? Alot of times coolant in the oil will cause bearing damage. I am extremely curious to here the outcome of your head gasket situation.

Not sure how much (if any) damage was done, but it runs perfectly fine. The dealer replaced the passenger side head gasket under warranty. It actually ran really good before I took it in. The misfire codes were tricky. They could not see any stored codes. They let it idle and eventually saw the codes live. I also showed them the oil analysis. Not sure if they even paid attention to it. Pretty happy they fixed it. They fixed it at around 21k miles. I have about 36k miles on it now. Runs great. Paint? Another issue...

 

[donshaw]

Faulty Spark Plug #3
Clogged or faulty Fuel Injector #3
Faulty Ignition Coil #3
Fuel Injector #3 harness is open or shorted
Fuel Injector #3 circuit poor electrical connection
Ignition Coil #3 harness is open or shorted
Ignition Coil #3 circuit poor electrical connection
Insufficient cylinder 3 compression
Incorrect fuel pressure
Intake air leak

These are the most likely possibilities and are the things I would check first.
Spark #3 bank 1 is thd second cylinder on the passenger side . Even cylinders are on the left (drivers side ) ( bank 2) cylinders 1,3,5 passenger side ..cylinders 2,4,6 (drivers side Bank 2) typing the codes in your internet browser will tell you alot .
303 or 30(3) spark plug #3 ...302 or 30(2) is sparkplug # 2
Plus it can also be Injector #3 or Injector #2
I agree with previous poster put a can of seafoam fuel additive to it . Premium gas on a full fresh tank and run the pissola out of it for a couple of days get on that thing get those rpms up to 3500-4000 accelerate more aggressively getting on the highway etc... if it doesn't clear out in a few days then look at that list and proceed. Sometimes babying an engine too much isn't the best thing for it.

Do the 2021 and up have the same lifter noise as the previous years? Ever since I have had this Gladiator there has been a slight tick. It sounded the same as my wife's 2016 jku with 9k miles

 

[Stan H]

Do the 2021 and up have the same lifter noise as the previous years? Ever since I have had this Gladiator there has been a slight tick. It sounded the same as my wife's 2016 jku with 9k miles

There are 4 cams and 4 valves for every piston 2 intake 2 exhaust. Thats 24 tappets sports fans. There is some noise. Now a loud tick is bad or a loud tap. However somewhere in 2020 or 2021 the rockers where discontinued and upgraded . I belive mine to have the newer style . As I have 117754 miles on mine and run the dog piss out of it. I just did a WOT this morning passing a creeping RV on a 2 lane byway . I rin and always have ran Amsoil 0W-20 change religiously also and my Jeep never sets for more that 2 days on the weekend . I let it idle for 10 min. Before pulling out and away we go !!. My Jeep was built in 6/20 so it is possible that earlier builds may have the older rockers and not be the newer style but I am fuessing yours is the newer one. The injectors in theses trucks are exposed and noise emanates from them . They make a tapping noise also . In the list of possible suspects injectors is one of the items in that list. The injectors aren't hard to repair literally unplug fuel and electric take bolt out and remove injector and replace in reverse order.

 

[Casique]

I had a slight tic, and used Archoil AR9100 Friction Modifier and it went away. Quieted the engine a lot.

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