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Misfire P0307

2007 Silverado Classic 1500, 5.3L engine, 233k miles.

Got p0307 last week, cleared the code and it hasn’t come back. I’ve checked for pending codes, still nothing. Went to check the $06 for misfires and I can’t get it to come up on my Foxwell scanner.

Question, it the engine supposed to be running for this test or will it show the last 3200 revs before shutdown? And is the $06 even available for GM vehicles?

Truck runs fine BTW. The CEL came on while waiting for gas at Costco.

Mode $06 is definitely available for GM vehicles

I use it all the time

I suspect your Foxwell scanner doesn’t have the capabilities of oem-level equipment . . . or you’re not familiar enough with it to get the data you want

you might have to manually enter component id and test id

You’re not still running the original plugs and wires . . . ?! :fearful:

have you performed a compression test?

Does your engine have AFM active fuel management . . . in other words, shutting off certain cylinders as needed?

First time I used it.

The manual for the Foxwell sucks. It is supposed to give $06 data but it says engine not running, ignition on. It says that for everything including fuel trim live data.

Still running original plug wires, new plugs though.

No compression test.

No active fuel management but is flex fuel.

I’m speaking from professional experience here . . .

It is extremely likely to damage the GM “coil near plug” ignition wires when removing them, no matter how careful you are

I’ve seen it happen countless times

so keep that in mind, in regards to that misfire

And don’t get hung up on P0307 . . . any misfires might not really be specific to #7. If you look at live data, it might be apparent that there’s plenty of misfire activity on other cylinders, as well

That makes no sense whatsoever . . . Mode $06 data is essentially stored data, not live data, so whether the engine is running or not should make no difference

That’s what I was thinking too.

BTW, this is not related to the ignition wire that was hitting the steering column that I posted about a couple of years ago, that was on cylinder #5.

I’m not hung up on P0307. That is why I wanted to look at mode $06 data because the P0307 has not returned, not even as a pending. I believe that P0307 is a two trip DTC so it had to occur on a second drive cycle withing three drive cycles after the first detection. Then it just hasn’t occurred since.

One thing I though might contribute was that the CEL occurred right after a two day rain, then it was dry after I reset the code. We just had another two day rain event and still no code.

I am thinking of replacing the spark plug wires and justifying it as PM. I don’t like throwing parts at a problem without knowing what it really needs and I really don’t like throwing parts at what could be a non problem.