Code p300

[GrubbyBaja]

Was there another code to go along with the P0300? Could you feel the misfire? I had a random misfire that would cause the check engine light to illuminate along with a noticeable cylinder misfire/drop out. I bought an OBD reader and kept it in the vehicle. When it occurred again, I plugged in the reader and captured a P0300 code which was accompanied with a P0303 and P2308 code. Ended up being a bad coil pack...~$70. You need to get the entire story.

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[Txrunner]

The oil change could be due to just looking for particles / debris if they expected sometime catastrophic but that seems premature. I would think they would look at the duty cycles of the fuel injectors, Spark plugs & gaps if recently replaced & coil packs/ wires. Good luck, i am dealing with this on an old Dodge Viper but have a great person looking systematically at it.

 

[pharmfrank]

As with any 'major' surgery a second opinion can't hurt, and to keep them honest I wouldn't
mention previous diagnosis. Modern engines should, under normal circumstances, go well
beyond 100K miles before internal 'exploratory surgery', IMHO

 

[ShadowsPapa]

In my line of work, we troubleshoot discrepancies a few different ways. The first own being, did you or someone else mess with it. The next would be environment/exposure to the elements followed by, is there a common/ known cause for the discrepancy. A history of trouble in the past would be another thing to look at.

You messed with it, start looking there. There are a few Cam/rocker concerns that would cause p0300. AutoZone could have given you the p0300 diagnostic and they could sell you a crate motor. That's pretty much where this dealer stands.

If you leave it with these clowns, do you think you could trust them to investigate further? At this point they are going to try and verify their assessment that you need a new engine.

I'm hung up on why change the oil on a engine deemed worthless.

And the bit about "you missed an oil change". Uh, if it was changed at 4K miles and these can go over 7, 8, maybe even more - then he's certainly not missed an oil change. Instead, he's probably changing more than necessary (not a bad thing, just proves he's missed nothing)
Even if it had gone to the point where the oil life monitor was triggered before a change - that's hardly reason for a blown engine!

 

[ShadowsPapa]

The oil change could be due to just looking for particles / debris if they expected sometime catastrophic but that seems premature. I would think they would look at the duty cycles of the fuel injectors, Spark plugs & gaps if recently replaced & coil packs/ wires. Good luck, i am dealing with this on an old Dodge Viper but have a great person looking systematically at it.

why would any shop do that?
Even a bad cam is going to show some things in the oil pan that don't belong. Hardly a catastrophic failure by any stretch.
That's a shade-tree way of diagnosing things.

With quality software, you can capture freeze frame info, a snapshot of what's going on.

Sometimes I struggle to see how these things can get so complicated - I get it when non-techs are trying to figure it out, but work in a shop and struggle for the most basic of troubleshooting when you have 10 times the information I ever had in a shop in the palm of your hand!
I had to know how to read scope patterns, how to test alternators with the usual suspects and an oscilloscope, and more. I didn't have things like this below, but I did fine.

2021/01/04 11:56:32.011: Faults found: P0303
2021/01/04 11:56:35.970: Faults found: P0303
Error code: P0303
Cylinder 3 ignition failures
Test not complete
Error intermittent
Error warning lamp not requested
CARB Freeze Frame:
___________________
Fault code: P0303
PCM Mileage since MIL On: 0.00 miles
PCM Odometer: 950.27 miles
Open Loop - Bank 1: No
Closed Loop - Bank 1: Yes
Open Loop due to Driving Conditions - Bank 1: No
Open Loop with DTC - Bank 1: No
Closed Loop with DTC - Bank 1: No
Open Loop - Bank 2: No
Closed Loop - Bank 2: No
Open Loop due to Driving Conditions - Bank 2: No
Open Loop with DTC - Bank 2: No
Closed Loop with DTC - Bank 2: No
Engine load: 30.20 %
Freeze Frame Engine Coolant Temp: 66.00 Deg.C
Intake Air Temperature: 215.00 Deg.C
Ambient Air Temperature: 12.00 Deg.C
Short Term Fuel Trim - Bank 1: 12.49 %
Long Term Fuel Trim - Bank 1: -3.13 %
Short Term Fuel Trim - Bank 2: 9.37 %
Long Term Fuel Trim - Bank 2: -7.04 %
MAP Voltage: 1.96 V
MAP: 46 kPa
Atmospheric pressure: 97 kPa
Engine RPM: 875.00 rpm
Vehicle speed: 0 MPH
Throttle Position Sensor 1 Percent: 12.94 %
Battery voltage: 14.58 V
Fuel level: 95.69 %
Purge Solenoid Current: 0.00 mA
Purge Duty Cycle: 0.00 %
Idle Air Control (IAC) Current: 0.00 mA
Idle Air Control (IAC) Duty Cycle: 0.00 %
EGR Flow: 0.00 g/s
Current Adaptive Cell ID: 24
Spark advance: -2.00 Deg
AC Clutch: Disengaged
EGR Gassed Flowing: No
Power Steering High Pressure: No
AC Switch: Off
PRNDL in Gear: No
Brake switch: Pressed

 

[Mark42]

Update, brought it to another shop, they they said miss fires on a multiple cylinders all on one side 2,4,6,8

said it could be cam but didn’t confirm. Suggested I’d get the engine replaced.
Same code. He said It only miss fires accelerating, not when it’s just idling.

I guess no one want to really repair it around here, should I try another shop?

or am I’m looking at a new motor…

thanks boys for all the input

 

[ShadowsPapa]

Update, brought it to another shop, they they said miss fires on a multiple cylinders all on one side 2,4,6,8

said it could be cam but didn’t confirm. Suggested I’d get the engine replaced.
Same code. He said It only miss fires accelerating, not when it’s just idling.

You don't have an 8th cylinder (but maybe wish you did??).

2, 4 and 6 are all on the left bank, US driver's side, that's bank 2.
What the heck is with these shops right away saying "you need a new engine".
Bluntly - BS (abbreviated as not sure Russ appreciates such words... .)

Try another shop that is willing to diagnose properly. If all you need is a cam and followers (and I'd do the lash adjusters while in there) that's thousands less than a new engine.

I'm just totally baffled that so many shops these days say "you have a misfire - you need a new engine".
Since the misfires are all on one bank, there are many possible causes - O2 sensors, among other things.


If I was younger - I think about all of the money I could make doing what other shops totally screw up or can't figure out..............

 

[Hootbro]

Update, brought it to another shop, they they said miss fires on a multiple cylinders all on one side 2,4,6,8

said it could be cam but didn’t confirm. Suggested I’d get the engine replaced.
Same code. He said It only miss fires accelerating, not when it’s just idling.

I guess no one want to really repair it around here, should I try another shop?

or am I’m looking at a new motor…

thanks boys for all the input

Someone has to at least open the valve cover and unfortunately, that is all drivers side bank for those cylinders and would mean at least the intake has to come off to look at left side bank.

Unless you have the means to do the work yourself, you are stuck in a negative loop of incompetence unless you can find a shop that will actually do what needs to be done. As you have seen so far, everybody want to go for the big ticket repair.

I do not know what your tolerance is for continuing to find a shop that will look at it correctly, but you have to also gut check and ask yourself if you want these same people doing the engine replacement?

 

[ShadowsPapa]

Someone has to at least open the valve cover and unfortunately, that is all drivers side bank for those cylinders and would mean at least the intake has to come off to look at left side bank.

Unless you have the means to do the work yourself, you are stuck in a negative loop of incompetence unless you can find a shop that will actually do what needs to be done. As you have seen so far, everybody want to go for the big ticket repair.

I do not know what your tolerance is for continuing to find a shop that will look at it correctly, but you have to also gut check and ask yourself if you want these same people doing the engine replacement?

So eloquently stated. A skill I totally lack.

 

[Lost1wing]

Only misfires on acceleration and on the even side is screaming cam and rockers. Suggesting an engine replacement without taking the valve cover off is insane.

If I were in your shoes, I would ask them to diagnose the ticking. It will require the valve cover to come off as well as the intake. If they can see cam lobe damage, I would be willing to install a new cam and rocker kit. If they don't see any cam lobe damage, maybe go with the engine idea. You would only have an hour or so of labor to at least look.

Sorry you didn't find a dealer willing to work on it.

 

[ShadowsPapa]

Only misfires on acceleration and on the even side is screaming cam and rockers. Suggesting an engine replacement without taking the valve cover off is insane.

Yes, I had forgotten that little detail - under acceleration is when it shifts into high lift mode, and that's where the issues lie with these, not in low lift.

Here's what I'd be tempted to do - IF IT WAS ME, and my money and my Jeep -

II'll make a deal with you - you pull that valve cover off and if it's NOT the cam and the cam looks great, I'll pay for that time. BUT I must be allowed to see the cam myself and take pictures.

IF the cam is toast - you fix it and that time is counted as part of the overall repair and nothing extra.

But then my head says - like Hootbro sort of "suggested" - would I want such a shop doing that sort of work?

(actually, I'd fix it, but if my situation didn't allow for that........... )

 

[Lost1wing]

Yes, I had forgotten that little detail - under acceleration is when it shifts into high lift mode, and that's where the issues lie with these, not in low lift.

Here's what I'd be tempted to do - IF IT WAS ME, and my money and my Jeep -

II'll make a deal with you - you pull that valve cover off and if it's NOT the cam and the cam looks great, I'll pay for that time. BUT I must be allowed to see the cam myself and take pictures.

IF the cam is toast - you fix it and that time is counted as part of the overall repair and nothing extra.

But then my head says - like Hootbro sort of "suggested" - would I want such a shop doing that sort of work?

(actually, I'd fix it, but if my situation didn't allow for that........... )

The OP is stuck! Would he want that shop replacing an engine? I'd take my chances with a cam job over an engine change, with either of those dealers. Less to screw up.

 

[Mark42]

Thanks bros I feel the same way, it’s wild to me that just looking at codes “you need a new engine, not worth the repair”

unfortunately I don’t have the means or place to open it, maybe when I was younger. I’m taking to another place tomorrow, a buddy of mine took his truck there for some motor work. I love the truck and want to keep it for a long time, hopefully this guy is willing to attempt to open the valve cover…

 

[Stan H]

You don't have an 8th cylinder (but maybe wish you did??).

2, 4 and 6 are all on the left bank, US driver's side, that's bank 2.
What the heck is with these shops right away saying "you need a new engine".
Bluntly - BS (abbreviated as not sure Russ appreciates such words... .)

Try another shop that is willing to diagnose properly. If all you need is a cam and followers (and I'd do the lash adjusters while in there) that's thousands less than a new engine.

I'm just totally baffled that so many shops these days say "you have a misfire - you need a new engine".
Since the misfires are all on one bank, there are many possible causes - O2 sensors, among other things.


If I was younger - I think about all of the money I could make doing what other shops totally screw up or can't figure out..............

PO300 ( it is the code for random misfire) can be a plethora of things fuel delivery, Ignition system failure blow head gasket , bad cam ,bad lash adjutors,etc...
Is the coolant low? Did you get a PO302,304 or 306 ? If any one of the other also came up it could mean it is centered around that cylinder or it is the worst. If nothing at Idle im going with lostwing & papa on this its possibly the cam. Why because its the highside follower than will fail lowside is idle up to 2800-3000k highside follower is above the 3k mark.

 

[ShadowsPapa]

PO300 ( it is the code for random misfire) can be a plethora of things fuel delivery, Ignition system failure blow head gasket , bad cam ,bad lash adjutors,etc...
Is the coolant low? Did you get a PO302,304 or 306 ? If any one of the other also came up it could mean it is centered around that cylinder or it is the worst. If nothing at Idle im going with lostwing & papa on this its possibly the cam. Why because its the highside follower than will fail lowside is idle up to 2800-3000k highside follower is above the 3k mark.

High lift will kick in when more "power" is needed, such as a heavy pull, towing up a hill, or when heavy acceleration is needed.
They start up in high lift as well.

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