denver110

Well here's what I found, valve stems coated white except for #4 and 6. Ash underneath soot. Is it ok to still replace the gasket and put it all back together? Gotta have it for Monday ya know

I know you all told me these trucks like certain brands, I'm buying the manifold gaskets today and gonna work on it this weekend, is there a particular brand this old hussy would prefer? She's turning out to be kinda moody so I wanna do it right

One video shows the gauge at 52 koio the started and bounces rapidly 50-55.

My fuel pressure is still low, idk if those leaks would do that. I just tried to link the video but says it's too large. ( only 10 sec).I'm not the best at this, I can turn a wrench but the diagnostic side is definitely my weak side. That's why I say I appreciate yall

I appreciate y'all helping me out with this I really do. I'ma gonna try to add some pics n video. I'll have to look at the PCM for brand, but definitely looks new . The plugs I bought was ngk and we're already gapped. The ones the guy put in was the same ngks which again makes me wonder why he changed the gap to 32. I did find some significant exaust leaks by hooking up a shop vac and using spray bottle. The exaust manifold is leaking pretty good on passenger side. And the gasket connecting the flange gasket pretty bad leak.

Not good at computers , so I'm doing my best to make this legible.Here's some more pictures got this code when it start bogging down to a stop. Hasnt happened again so far

Few months ago I bought a 04 Sierra. Ran great for exactly 103 miles then problems started . Seller told me it still had 02 sensor code showing ( I'll post pics) even though he'd replaced all 4 twice . This going to be long cause I want it all out there. He replaced the following to my knowledge. 02's, map, maf, ect, PCM, throttle body, plugs, wires, coils , injectors, pretty much everything but knock sensors. I replaced 1 o2 because I saw 1 (new) was bent. Problems started with loss of power and MPG. Started running very lean. Using multimeter I've checked the wiring on everything and it all seems fine. While troubleshooting the power loss and gas mileage past few weeks , 2days ago it's developed a misfire. When you start it about 15seconds in it starts missing and sounds like crap. Like running on 3 cylinders or something. It's not everytime and when it happens turn off and on and your good . Last night I went through the plugs and gapped them at . 40. They were all . 32 for some reason. I check fuel pressure, it holds at 52. So I'm thinking bad injector? I've tested 5 so far (ran outta time) 1,2,4,and 6 show 13.1-13.6 #8 shows 12.9 Still have to check 3,5,7. But as you see in pics , problem is on bank 2. I know this is long post, I hope someone reads it all lol. Some of the spark plugs keep loosening. Like very loose. I Never had that problem , they are the right size too . The 2 pics of 02 banks volts I'm thinking shows at bad B2 CAT . I I right on that?

Buddy at work said after replacing those o2's I would need someone to flash my ecm. How or where would I go about that?

Just bought an 04 sierra with EXACTLY THE SAME ISSUES . EXACTLY. Guy that sold it replaced everything sensors, gaskets, plugs ect. Even the PCM. Told me upfront it had codes for 02 and knock sensors but came back after replacing them. He couldn't figure it out. Even had the receipts. Well the truck has lost a lot of power and drinks the gas! Buddy of mine said I need to have someone clear my computer and while their at it delete the EVAP stuff. Anyone know if that would fix this guys and my issues?