Any codes, or just the idle miss?
What did you do to your NNBS GMT900 Tahoe/Yukon Today?
- Thread starter phattyford
- Start date
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.99 cents each, less than 1 cent each? LOL
$11.88 + 9% tax that usually last's me about 3 months roughly, 2 bottles per truck on a full tank, usually filling these things up about once a week give or take.
I take turns on them drive one then drive the other one the next day, roads trips usually in the Yukon, I want to buy a G8 GXP, maybe a SS if the price is right but I like the Pontiacs more.
No codes, just the miss. And it’s only occasional and brief. Never persists more than a second or two. I can’t replicate it on demand.
you could hook up a scanner and see if there is any actual spark miss going on, then maybe check the fuel pressure just to verify it's good at idle, if there is no issue then I would just clean up everything and do the injector service, if that doesn't fix it maybe move on to basic tune up, plugs, wires, if it persist's and is not a spark miss then maybe replace the throttle body.
if there is a spark miss it could be plugs or coil packs, injector, or the harness, vacuum leak, cam sensor. and worst case scenario internal engine damage.
i'm probably missing something and if it's running fine otherwise then it's probably something simple
what is the mileage? after about 160k the maf's are questionable in my book and should be replaced those things can do all kinds of stupid stuff, make the engine run like ******* and cause the transmission to shift weird among many other things.
Have you had the plugs out? I had a low idle miss that seemed to come and go, also no codes. It turned out my plugs had gotten fouled from oil consumption, a few much worse than others. In my case it was the whole AFM relief valve, down rev valve cover, that lead to a downward spiral of oil consumption and the miss was just the canary in the coal mine of bigger issues.
Not saying that is that case here, might just be a marginal plug, wire or coil pack.
As @Doubeleive mentioned, a cheapo ODB scanner might allow you to isolate which cylinder(s) has the miss. You could just sit and watch the counter increment as you felt the miss.
So, today I got some more information. I don’t know yet if this is the same problem causing the idle miss or an all new separate issue.
Truck runs fine all morning, then way back in the mountains on a dirt trail in 4 Low it starts stalling and the MIL comes on.
P069E status $07E8 Fuel Pump control module requested MIL.
P0191 status $07 EB Fuel Rail pressure sensor circuit range/performance bank 1.
P0171 status $07E8 system too lean bank 1.
I was able to limp it out a mile or so by intermittent rest after it stalled. Each start it would start out running OK and within a minute progress to stumbling, losing power, and ultimately stalling again. This behavior had me thinking it was heat related.
Once I got to a better piece of trail I took a longer break. Opened the hood to vent heat; hosed down the FPCM with brake cleaner to chill it.
After that I departed in 4H and with enough travel speed to help cooling. No further problem 60 miles back home. Over mountain passes where it was WOT at times, and interstate speeds. So it’s absolutely not a clogging filter or inability of the fuel pump to deliver.
???
Truck runs fine all morning, then way back in the mountains on a dirt trail in 4 Low it starts stalling and the MIL comes on.
P069E status $07E8 Fuel Pump control module requested MIL.
P0191 status $07 EB Fuel Rail pressure sensor circuit range/performance bank 1.
P0171 status $07E8 system too lean bank 1.
I was able to limp it out a mile or so by intermittent rest after it stalled. Each start it would start out running OK and within a minute progress to stumbling, losing power, and ultimately stalling again. This behavior had me thinking it was heat related.
Once I got to a better piece of trail I took a longer break. Opened the hood to vent heat; hosed down the FPCM with brake cleaner to chill it.
After that I departed in 4H and with enough travel speed to help cooling. No further problem 60 miles back home. Over mountain passes where it was WOT at times, and interstate speeds. So it’s absolutely not a clogging filter or inability of the fuel pump to deliver.
???
RooTBeeRthe1st
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Very peculiar
swathdiver
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Some bad fuel was my first thought until seeing this post with the fuel pump related codes. Have the Tech-2 run an injector test, maybe one got stuck or something.
my guess is the fpcm or fuel pump is becoming problematic
might want to pick up a fuel pressure tester, there cheap like $30 at harbor freight, you should have a I think a minimum of 42-43psi at idle but most will run a tiny bit higher like 45-50 or so if normal.
the fpcm harness are known to get corroded, might want to get under there and inspect it, pull the harness off and clean it up if needed.
might want to pick up a fuel pressure tester, there cheap like $30 at harbor freight, you should have a I think a minimum of 42-43psi at idle but most will run a tiny bit higher like 45-50 or so if normal.
the fpcm harness are known to get corroded, might want to get under there and inspect it, pull the harness off and clean it up if needed.
