95escahoe
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Rough idle only in cold weather? Please help
- Thread starter edd112
- Start date
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Just to update you on my Tahoe, which also has a bad misfire on a cold engine. I just changed plugs and wires, and moved a coil from cylinder 4 to 2 (I have a bad misfire on cylinders 3 and 4. ) l still have a bad misfire on cylinders 3 and 4. I am also getting a lean condition code on both sides. I now suspect it's the intake manifold for me. I guess temperature really can affect it that much.
Larry
Larry
Further update: did the intake manifold gasket today. I didn't have time to do the knock sensors, but I did look at the rear one and it was dry and still shiny. I'll see about doing them in the summer, maybe.
My rough cold idle is solved. I could get no confirmation of a leak using the carb cleaner trick. Don't take a negative result from a carb test to mean the intake gaskets are good. They may still be bad.
Larry
My rough cold idle is solved. I could get no confirmation of a leak using the carb cleaner trick. Don't take a negative result from a carb test to mean the intake gaskets are good. They may still be bad.
Larry
bottomline, I used the Felpro metal framed gasket also. I don't think it's so critical on our intakes, but I know they're good. The metal intakes were critical to use on the GM 3.8 which had coolant passages. Hot coolant that has gone acidic would eat through the nylon gaskets like a rat. And that early Dexcool, at least, wasn't so long life as they would have hoped.
I gave it a good test run tonight. Nice smooth idle. I saw LOTs of leakage through cylinder #2, exactly where I was getting misses.
By the way, lots of people say to dispense with those sponge things under the intake. I can vouch for the fact that those sponges actually did keep things a little cleaner in there. I didn't do the GM TSB regarding the RTV sealant around the knock sensors. I also noticed a lot of dirt/oil/soot buildup along the top back of the engine. It didn't seem fresh wet, so I can't prove or disprove my oil leak source from there. I do have a replacement oil switch too, but it was getting cold and dark so I skipped those steps today.
I gave it a good test run tonight. Nice smooth idle. I saw LOTs of leakage through cylinder #2, exactly where I was getting misses.
By the way, lots of people say to dispense with those sponge things under the intake. I can vouch for the fact that those sponges actually did keep things a little cleaner in there. I didn't do the GM TSB regarding the RTV sealant around the knock sensors. I also noticed a lot of dirt/oil/soot buildup along the top back of the engine. It didn't seem fresh wet, so I can't prove or disprove my oil leak source from there. I do have a replacement oil switch too, but it was getting cold and dark so I skipped those steps today.
bottomline2000
Full Access Member
Yeah I don't think the felpro is critical but it is more robust than the plastic framed gasket.
I thought about leaving those foam guards out as well. Hindsight is always 20/20..
Sent from my SAMSUNG-SM-T377A using Tapatalk
The foam guards may have actually worked as intended in my Tahoe. As I said, that rear knock sensor was in perfect shape. There was a little debris in there, and some soot buildup, but it was a lot less than on the outside of the foam guard. I thought about removing them, especially the rear one as recommended by the TSM, but when I saw how much soot there was on the block just outside the foam insert, and how little there was inside, I left it in for now.
I do have an oil leak somewhere. It could be near the top end, but I do think my oil adapter gasket needs changing as I think that may be the majority of my leak at the moment. I'll do that at the next oil change I think.
Larry
I do have an oil leak somewhere. It could be near the top end, but I do think my oil adapter gasket needs changing as I think that may be the majority of my leak at the moment. I'll do that at the next oil change I think.
Larry
I believe my 5.3 needs intake gaskets as well. Any trip to cold temp areas and I get P0171 & P0174 (Lean both banks).
My engine is exactly as you described on top -valve covers, intake, etc
""I also noticed a lot of dirt/oil/soot buildup along the top back of the engine. It didn't seem fresh wet, so I can't prove or disprove my oil leak source from there.""
Oil leak from where would cause that dirt/dried oil/soot buildup?
Would you mind sharing the TSB you are referencing as I am going to do intake gaskets soon.
Here you go:
http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=115747
The www.revbase.com site has a ton of great info. I found out about it from another forum before I got run out of town for being a Tahoe owner! (ssshhhhh... don't tell anyone!)
Larry
http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=115747
The www.revbase.com site has a ton of great info. I found out about it from another forum before I got run out of town for being a Tahoe owner! (ssshhhhh... don't tell anyone!)
Larry
Thank you! Looks like the TSB won't apply to me since I'm in an '04. Thanks again.
Now if I could locate the source of the dirty top side, have the dirty bottom side too, but it's wet and drippy down there....I'm thinking rear cover and/or oil pan.
Now if I could locate the source of the dirty top side, have the dirty bottom side too, but it's wet and drippy down there....I'm thinking rear cover and/or oil pan.
rockola1971
Full Access Member
Check your oil cooler lines.
