So here's an update. Over the weekend I decided to tackle the exhaust manifold bolts. Figured they needed to be done anyway. Unfortunately, the rear most bolt broke off about an 1/8 inside the head, so I ended up having to take the head off, doing a head gasket and intake manifold gasket. Even replaced plugs and wires again since they had to come out anyway just to be safe. Not to mention the exhaust manifold and catalytic converter gaskets. Good news is it fired right up, runs as good as it ever has, and (having cleared the code before hand) the code hasn't come back up yet. I guess I'll be back if it does... Thanks for the suggestions.
Gotcha, so then it seems things are normal there then. I did just realize my fuel pressure is consistently 43-44 psi though. I don't know if the scanner reading is as accurate as an actual pressure gauge would be, but the fuel pressure should be more in the 50-60 psi range no? Then again I'm not sure that's related to my problem.
I have some of it recorded here but honestly, I don't know enough about fuel trim to know what it really means. Long term stayed at 0 to 0.8 during idle. More or less the same for short term. Though a couple times the short term went as low as -14%. I know you ideally don't want to be outside a -10% to 10% range but, I don't know how far off that really is.
Both were replaced a few months ago. Engine runs fine, no misfires if that's what you were thinking.
Hello, I know this code is fairly common so I apologize for starting another thread on it, but none of the info I've found has helped. I have a 2008 1500 Silverado with a 4.8. Had it for 4 years and it's run great, until today when I got the code. I know that 95% of the time its the catalytic converter, but I've tested mine and they seem fine. Using a scanner, the O2 sensors read as they should based on what I've found. Both upstream sensors fluctuate as they should between 0 and 1 volts, and the two downstream sensors remain consistent as they should, fluctuating between .73- .77 (Bank 1) and .77-.8 volts (Bank 2). I tested that both at idle and at 2200 rpm. A temperature check of the cats shows about 430 degrees on the intake and 550 or so on the exhaust. Tested this at high RPM also. I am missing a couple of exhaust manifold bolt heads, but I have no sign of a leak, runs quiet too. I was thinking about spraying soapy water on the exhaust when it cools down and then running it to see if there are any leaks. Other than that, I'm at a loss. I mean the readings the O2 sensors are giving seem to imply they are fine too right? This is my daily work truck, and I want to get this figured out as soon as I can. I smelled gas a couple times today, and I know that if my cats aren't bad yet, they will be soon if it runs rich. Actually had this same problem on a 2000 Silverado before this truck. Replaced all O2 sensors, cats, and manifold gaskets chasing the problem and never could get it to stop running rich and showing the code, so I'm very motivated to solve this before something worse happens. Don't even mind spending the money or doing the work, just can't figure out whats wrong... Anyone have any idea what might cause the code besides the cats and O2 sensors? Or do my readings actually mean something is bad?
Most OnlineNewest Member
Who's Online 85 Members, 1 Anonymous, 2,514 Guests (See full list)
- Fishin' VA
- Dick Lichon
- [email protected]
- The G-Man
- Dean Sterling
- Tim Terry
- TX USMC VET
- HK GUY
- My First GMC
- Levi's 96 gmc