Another P300, but need advice

[Grinnbold]

I hate that this is my first post, but I need some help and not really sure where to turn...

I picked up my Gladiator on January 2nd. Near the end of February, I was leaving to go get some food and when I started the truck the auto stop/start was disabled for some reason. I was in a hurry so I ignored it and took off. I got to the drive-thru pulled in and the truck killed itself because the stop/start system "fixed" or re-enabled itself. I didn't think a whole lot about it, but when it started back up as I pulled forward I had a flashing CEL. I immediately killed the tuck and pulled the codes. P300. CEL wasn't flashing anymore and I never felt or heard anything in terms of missing/knocking etc. Finished going through the drive-thru and called up the dealer and setup and appointment.

Without going into detail of the dealership, they found nothing.

On July 4th, the exact same thing happened. This time the CEL didn't stay illuminated after restarting when the CEL was flashing. The next day (Sunday), it happened again, this time the CEL stayed on. First thing Monday morning I called the dealership and setup an appointment. I was told as long as it's not flashing no problem, just come in and we'll look at it but it's probably the same thing as the last time.

I didn't drive the truck until I needed to take it to the dealership. On the way to the dealership, the CEL turned off. The service guy told me if the light isn't on they can't help me. So I argued that the code is stored and had to convince him to look at the vehicle. He finally decided to take the vehicle after he pulled the codes and saw the P300.

The dealership called me back and told me that this will not be covered under warranty because you have bad gas in your vehicle. Also, in order to keep your warranty you will need to replace the catalytic converter, all 4 o2 sensors (because they are damaged), drop and drain the gas tank, then put new gas in the vehicle. I pressed him on how "bad gas" is going to damage those components so quickly as I only have 4800 miles on the vehicle; to which he told me, you are a victim of bad gas, it happens. I asked him how they tested and what they found and he told me they found heavy metals that measured 7.6 (unfortunately I'm unfamiliar with this measurement and am having trouble finding info on it).

Soon after I let them know about TSB 18-053-20 which he said was flashed onto the vehicle and I was still receiving P300 after the update. I'm unsure if this is stored or if they had another flashing CEL at this point.

I did call FCA after this and messaged JeepCares on this forum for some help and awaiting a call back from a representative.

So my questions would be:

1. Could heavy metals at this measurement actually damage the cat and o2 sensors this quickly? (my assumption is no) - BTW this tank of gas was only used to drive about 30-40 miles, and was filled up at a Shell in south Austin that I have never been to. I usually use 1 of 2 gas stations near my house a Shell and Exxon. Both of which I never had issues in my JK or my SRT4.
2. Any ideas on where or what I can do next?

I have already setup another appointment at a different dealership for next Tuesday. I'm a little hesitant to go get the vehicle as they are trying to make me pay close to $1,000 for diagnostics and the ECU update which they said was not needed by my specific vehicle.

Sorry for the long winded post, hopefully I didn't leave anything out...

-Grinn

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[nerubi]

From a mechanic site:

P0300 Causes
(* = Most Common)

• Faulty or worn spark plugs *
• Faulty spark plug wires or coils *
• Distributor failure *
• Faulty fuel injector
• Vacuum leak
• Low fuel pressure
• Camshaft sensor defective
• Crankshaft sensor defective
• Engine timing off
• Leaking head gasket
• Low engine compression
• Poor quality fuel

Code P0300 Severity – Severe

P0300 should be repaired immediately. Ignoring this error could result in ignition failure, catalytic converter damage, and unsafe/dangerous conditions while operating the vehicle.

 

[Retro Bait]

I am not buying the "bad gas" excuse. Have them provide the gas chromatography report on gasoline that shows all the metals and so forth...I'm betting they can't.

Your vehicle is having a multi/random misfire. This can be caused by a lot of things and can be very difficult to diagnose. The 1st thing I would do is pull/inspect/replace the spark plugs. This is cheap and spark plugs (even with low mileage on them) can cause a lot of heartache.

I had a 93 chevy truck that I installed brand new Bosch platinum plugs in years ago and it would not idle for shit. Had to go back to AC plugs.

If more than one cylinder misfires, this will increase or decrease the revolutions per minute (RPM) of the crankshaft. If that increase and/or decrease is more than 2 percent, the Powertrain Control Module will store the P0300 trouble code.
If the percentage of the increase or decrease in revolutions per minute (RPM) is between 2 percent and 10 percent, the Check Engine Light will come on. If the percentage of the increase or decrease in revolutions per minute (RPM) is greater than 10 percent, the Check Engine Light will blink on and off, as to alert the driver of a more serious misfiring problem. The P0300 trouble code indicates that there is a misfire in random or multiple cylinders.

 

[Renegade]

https://www.jeepgladiatorforum.com/forum/threads/multi-cylinder-misfire.20338/

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