Cylinder 8 misfire and more...

Back to the dealership this morning after picking the Raptor up yesterday for codes P2629 and P2610 (bad O2 sensor).

Driving home last night and truck started hesitating while cruising at 70mph (the speed limit on the tollway). The check engine light came on solid, then started flashing (usually a misfire).

I limped it home and pulled the codes...P2197, P0151 and P0308. That is on top of P2629 and P2610 that I got two days ago.

I hope the dealership fixes the issue this time.

FWIW...the truck has 6k miles.

keep us posted!

At least you didn't get a P0300, rapid misfire. My Shelby did that over the weekend. It was caused by fouled plugs. The fouled plugs was from a bad tune that had too much fuel and too much timing in the engine.

Raptor62 said:

At least you didn't get a P0300, rapid misfire. My Shelby did that over the weekend. It was caused by fouled plugs. The fouled plugs was from a bad tune that had too much fuel and too much timing in the engine.

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Yeah, P0300 is a bitch. My CTS-V had that code for about 3 months until finally something broke and I ended up with P0308. Cylinder 8 decided not to work anymore. The engine is being torn apart now. P0300 can be very hard to diagnose.

On a good note, the dealership called and said they fixed the problem. They said it was a wire leading to the O2 sensor that was chafing against the frame. They replaced and secured the wire. Hope that fixes it.

whisler151 said:

Yeah, P0300 is a bitch. My CTS-V had that code for about 3 months until finally something broke and I ended up with P0308. Cylinder 8 decided not to work anymore. The engine is being torn apart now. P0300 can be very hard to diagnose.

On a good note, the dealership called and said they fixed the problem. They said it was a wire leading to the O2 sensor that was chafing against the frame. They replaced and secured the wire. Hope that fixes it.

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Glad to hear it was something simple to fix. I was glad that a set of plugs fixed the problem. The goes out of warranty at the end of this month.

Raptor62 said:

Glad to hear it was something simple to fix. I was glad that a set of plugs fixed the problem. The goes out of warranty at the end of this month.

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That is good. My LS2 is too modified for the warranty to kick in. Most GMs have 100k mile powertrain. My service adviser said as long as my mod doesn't directly cause the problem he'll fix it.

whisler151 said:

That is good. My LS2 is too modified for the warranty to kick in. Most GMs have 100k mile powertrain. My service adviser said as long as my mod doesn't directly cause the problem he'll fix it.

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That is what my dealer said. So far, I haven't had to test that theory.

Raptor62 said:

That is what my dealer said. So far, I haven't had to test that theory.

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I hadn't either...until cylinder 8 was misfiring 1000 times a minute. We'll see what the culprit is. In the mean time i'll have a fresh LS2.

Raptor62 said:

At least you didn't get a P0300, rapid misfire. My Shelby did that over the weekend. It was caused by fouled plugs. The fouled plugs was from a bad tune that had too much fuel and too much timing in the engine.

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R62, P0300 is a random misfire and it simply means that the misfire monitor cannot identify a specific cylinder. Tunes like you mention are often a cause of a random misfire. Things like RFI and MAF readings that are skewed are also common culprits.

FSM

whisler151 said:

Yeah, P0300 is a bitch. My CTS-V had that code for about 3 months until finally something broke and I ended up with P0308. Cylinder 8 decided not to work anymore. The engine is being torn apart now. P0300 can be very hard to diagnose.

On a good note, the dealership called and said they fixed the problem. They said it was a wire leading to the O2 sensor that was chafing against the frame. They replaced and secured the wire. Hope that fixes it.

Click to expand...

whisler, not to be condescending, but I am very skeptical that a chaffed wire to a O2 sensor is causing a misfire code. I am not sure what model year your vehicle is, but O2 sensors have not been used for direct fuel delivery since early to mid 90's. They are merely feedback sensors to the PCM. Also, I am a little concerned that the engine is being torn apart to find a chaffed wire to an O2 sensor?! Did I understand that right?

FSM