I'm just going to copy and paste my posts:
Well I will first start off with some background.
Over the weekend, I replaced my passenger side exhaust manifold gasket and fixed and extracted a broken header bolt by cylinder #8. Although a bit of a pain, everything seemed to go well and I got the bolt out and everything reassembled.
I then took the car out for a drive to the grocery store and back with no issues.
Fast forward to this morning. I had to take my kid to the doctor and I fired the Tahoe up and noticed right away that it was not firing on all cylinders. After I got back, I pulled up my codes and did a quick scan via HPTuners. I got a misfire code for Cylinder#8. My scan showed misfire counts around 180 at idle and the O2 sensor and fuel trims indicated to me that fuel was being injected and then unburnt. That seems to indicate that I have no spark in that cylinder.
I swapped a spare wire I had and also replaced the plug and there was no difference. My next step is to switch the coil-packs around.
I should also add that the Tahoe spent the night sitting out in a fairly heavy rainstorm and got very very humid, things that normally don't get along with electrical systems.
So my next step is to put in a new coil-pack and see what happens. I am hoping this will remedy the issue.
If this doesn't rememdy the issue, where should my next step be?? Compression check? Fuel injector? I don't know and could use some direction.
So I just thought I'd update.
I went to the parts store and picked up a new coilpack. I changed it out in the pouring rain and voila! she's back up and running again.
I'm glad it was just the coilpack and I didn't have to go any further....
Dammit......
I drove my Tahoe into work today. For most of the ride it was running fine. I was almost to work and was sitting at a light. I started noticing the same sputter again.
I stepped on the gas and the truck started shimming again and the SES popped back on.
I can't check the codes yet, but I'm willing to bet it's the same cylinder misfire. If that's the case, I'm leaning torwards a leaking injector. Considering that it was running fine with the new coilpack tells me that it had a strong enough spark to ignite the extra fuel, but as time went on, the extra fuel probably fouled out the plug.
Next in line, a fuel pressure test and probably a new injector.....
So do you think I am on the right path? I'll know more tomorrow when I can get it on the scanner and tear into it some more.
Oh, the specs are an '06 Tahoe with the 5.3 flex fuel v8