Bad misfire

[cj5]

Hi all I have a 2007 Suburban ltz it has the 5.3 at 200,000 miles on it. So far it eat oil like no other and I had to replace the lifters once at 180k. It ran good for 20k miles after I did the all new lifters untill Sunday when it started misfiring bad and the check engine light can on with the traction control and stabilitrac which is exactly what it did when the AFM lifter went out last time. As of now I have pulled the valve covers and watched all the rockers move when turning the motor over and they all seem to be good I went over them all a few times watching them to be sure then I put it all back together and checked spark at every spark plug. Where else should I be looking?

 

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[cj5]

Heres a picture of the spark tester I used

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[Dnt]

If it is a oil burner it may have just fouled a plug,  I bet you did not thread your checker gadget onto each separate plug did you?  What were your readings from your compression check?  

[cj5]

No the checker just checks spark at the end of the plug wire. The plugs are pretty new like maybe 4k or 5k. What will a compression test tell me? I called a local mechanic and he said he'd guess the circuit under the intake but he was guessing over the phone. I can get back out there and do a comp test if it'll help diagnose the issue

If it is a oil burner it may have just fouled a plug,  I bet you did not thread your checker gadget onto each separate plug did you?  What were your readings from your compression check?  

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[Dnt]

I had a 2009 that was an oil burner it fouled out several plugs over the 88k miles that I owned it. Was usually the drivers side second from the front. Pull that plug right quick and check it out. The compression check will tell you if you have lost a valve. Hopefully just a simple fouled plug easy fix.  

[cj5]

Here's the first three passenger side plugs closest is the front

I had a 2009 that was an oil burner it fouled out several plugs over the 88k miles that I owned it. Was usually the drivers side second from the front. Pull that plug right quick and check it out. The compression check will tell you if you have lost a valve. Hopefully just a simple fouled plug easy fix.  

So far third from the front on the passenger side is the most messed up it looks to be missing a small chip

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[Dnt]

Definitely a misfire there on that one with the chipped ceramic. Could have just been a bad plug from the factory? They are all dark so looks like you do have an oil burner.  i was keeping a 5 quart container of oil in my 2009 truck. Everytime  filled up with gas I filled up with OIL.   

[cj5]

Yeah it's definitely will bring her I'm down to about a court every week and a half or at least that's what my wife tells me when she puts it in I don't know if it was shipped from the factory I'm going to put all new plugs in it tonight and might as well do compression test while I have them all out I'll let you know how it goes

Definitely a misfire there on that one with the chipped ceramic. Could have just been a bad plug from the factory? They are all dark so looks like you do have an oil burner.  i was keeping a 5 quart container of oil in my 2009 truck. Everytime  filled up with gas I filled up with OIL.   

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[cj5]

Ok well on the test run ran way better but then my oil pressure dropped to 0 and said shut engine off. I shut it off and let it sit and started it again and it did it again so I putted home and listen for any engine noise and there was none is there a second location for oil pressure senser. I know about the one right on the back side of the intake

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[Dnt]

dont think there is but one oil pressure sensor on these GM 5.3 engines. Wondering if you might have pulled the wire loose at the sensor while trading the plugs out?  Just seems like too much of a coincidence that this happened immediately after the plug change......

[cj5]

I agree I looked and it was still hooked up I'm gonna just swap the sensor and pull the screen out and clean it really well and see how that goes

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[cj5]

Well I changed the sender and I cleaned the shit out of the filter it was so clogged i couldn't see through it and I changed the oil and filter at the same time. The thing runs good and has way better oil pressure then before now runs over 40 while moving and 25 idle

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[Supreme Pizza]

Sweet. 

 

I wonder if its your rings, or the valve guide seals that are leaking oil. 

 

If its the rings, a different grade oil, or perhaps additives might help a little.

 

If its the valve seals, I would try this stuff: