SOLVED! '07 TAHOE 5.3 MISFIRE AND STABLE TRAC OFF AT SAME TIME

#1
As title says, I am getting random misfire on #4 and traction control off warning at same time. 1st & 2nd time it just felt like I hit something with left rear tire or like just that brake snapped on for a second. Then today the 3rd time but had CEL and bad misfire and traction control off showing in DIC. Condition were 80-90 degrees, 20 minutes on highway at 65-70 MPH. Rough ran it to destination barking left rear tire on every take off, I was not gassing it that hard. 3 hours later ran fine with normal twitches at idle its always had. Ran 70-75 for 25 miles home w/o issues other than CEL stayed on. How is misfire and TC connected?
 
#2

Edit: My bad. Not the same engine however the principles are the same. Only difference is the V8 has spark plug wires. Swap that with a good cylinder. And as I learned, these engines are also sensitive to the type of plugs used. Use only iridium NGK or ACDelco plugs specified for this engine.
 
#3
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#4
Thank you for responses. I had a 04 TB before the Tohoe and understand the differences. AC Delco iridiums with new wires maybe 8000 miles ago. I will read and watch your info tomorrow as family is interrupting right now. haha FYI. The TB is why I joined another forum in witch I followed over to here. Some may know the story on that. Im thankful you are all here and helpful.
 
#5
As for the traction control, that is likely a totally separate issue. You would need to pull the codes for that and the only thing we know short of a Tech 2 or other high-end scanner, is a bluetooth OBD adapter and Car Gauge Pro for Android.

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#6
Update. I switched coil packs between 1 and 4. Tahoe continued to run normal the few short trips I made during the week It does not get driven daily as I have company truck for work. Friday night we made similar trip to a Scout camp out, no problem. Today, Sunday, it started again on the way home. Again #4 eliminating coil pack. I checked for spark and I have spark. Pulled plug from number 4 and it is soaked with gas telling me injector works. Did compression test on cyl 2 and 4. #2 hit 110 psi running for a few seconds. #4 has 0 psi. Also noticed rocker rattle on left bank. I read that 1, 4, 5, and 7 are DOD cylinders. My theory that I don't like is, DOD lifters are bad or stuck and AFM? is still sending fuel. No air with valve closed so no combustion with spark and fuel? No back fire noticed. What keeps cylinder from compressing in 4 cyl mode. Any thoughts on this worst case scenario? Thank you
 
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#7
Just recalled something that may or may not be relevant. The last time I change oil it was early due to bad oil. I was not getting oil pressure to sending unit due to little gel like lumps in oil blocking port to sending unit. Thought it was bad sending unit and I replaced it only to have the same issue. Don't no why, but I decided to change oil and that solved that. I would change it twice right now if that would fix this current could be expensive problem.
 
#8
0 compression means that you need to go into the engine deeper. Take the valve covers off and check the movement of the rockers, Could be a dead AFM lifter.
 
#9
Fixed. Cylinder 4 had a collapsed-stuck lifter. $3000 got all new lifters, sensors, oil change, ect. at my independent /non dealer shop. The cam fortunately was not harmed. Didn't realise it was a little noisy before until I got it back and barely can hear it idle. I also know now that the 1st 100k miles of it's life didn't get proper oil changes. At 165k now. Now I would like to get a tune if I could find someone local to St. Louis metro area. I know of a 4x4 shop but there pricey. Thanks for the advice. I recommend GMTNATION.COM to everyone with GM truck/suv having problems. I don't know how to change the "need help" in 1st post, guess I need help with that. Thanks again.
 
#10
Glad you got it fixed, also the seals inside that AFM manifold can leak oil pressure and it wont make that cylinder's lifter extend out to open valve. I seeeent it happen.