Howdy folks, long time since I posted on here. 2007 Yukon with 206K on it. Got the stabilitrack and traction control lights pop up and truck started running horrible. Was able to limp it off road and get towed. I scanned it while waiting and I think it was a P300 and P0455 codes that came up. My garage tells me I have no compression on two cylinders and one is super low. Said my options are to tear into it and potentially change lifters and/or cam if damaged and figure out what else is wrong. Or, put a new engine in it. This place has never treated me wrong, so I'm a bit confused as I honestly though this was a simple ECM/PCM issue or some kind of electronics causing this like the mass air flow sensor or PCM etc etc. Thoughts please? Thanks!!
Stabilitrack and traction control lights
- Thread starter tights24
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I think it is common for the Stabilitrack and TC to light up when you have hard misses.
Did they tell you which cylinders had little/no compression?
When they did the compression test, did they do anything to help isolate the problem (valves vs rings), etc?
Did they tell you which cylinders had little/no compression?
When they did the compression test, did they do anything to help isolate the problem (valves vs rings), etc?
They did tell me which cylinders but honestly I forget. I was to say 2 and 4 and another had super low compression. The one thing that was odd to me that I forgot to ask about was the fact that when it started acting up on the highway I pulled over and it was idling super rough. When it was sputtering enough like it was on the verge of stalling if I put it into neutral it ran fine. Which I would have thought pointed to an electrical issue. However, when I started it up to back it out and get it on the flatbed it ran rough regardless of whether it was in park or not. Maybe putting it into neutral when it first started was just a fluke that it ran ok......They also mentioned that they could dig into the engine and verify if it's lifters or cylinder heads or pistons(forgive me, not a mechanic when it comes to internals), but at that point the cost could just keep going up and up, and it may end up being cheaper to just get a replacement engine. Of course the first thought that entered my mind was, if I'm doing that I may as well put the 6.2 in it and swap out the transmission too. lol. Probably not that easy though. I also found another post that stated:
"About 30K miles ago, with about 95K on the clock, with our 5.3L 2007 Yukon, I noticed a low idle miss. The dealer debug started with the PCV and along the way found it didn't have the valve cover upgrade. They did some more diagnostics and determined I was getting some oiling on a plug primarily due to a piston ring issue.
GM paid for all the parts (new valve cover, 8 pistons, 8 ring sets, etc., etc. etc.) My dealer installed it all very cost effectively for me. Great support from GM. Zero issues since, runs like a top."
This was from December of last year so I confirmed that this was actually done at that point with their truck that far out of warranty and they said yes.....
"About 30K miles ago, with about 95K on the clock, with our 5.3L 2007 Yukon, I noticed a low idle miss. The dealer debug started with the PCV and along the way found it didn't have the valve cover upgrade. They did some more diagnostics and determined I was getting some oiling on a plug primarily due to a piston ring issue.
GM paid for all the parts (new valve cover, 8 pistons, 8 ring sets, etc., etc. etc.) My dealer installed it all very cost effectively for me. Great support from GM. Zero issues since, runs like a top."
This was from December of last year so I confirmed that this was actually done at that point with their truck that far out of warranty and they said yes.....
I think many times, very competent shops prefer to swap someone else’s reman into a vehicle as the warranty issues are on the engine builder. Frankly, I think a quality reman is a really good way to go if the truck is in otherwise good shape.
On the other hand, if it is a beater of a truck to start, sometimes it is better to get what you can selling it to someone who can revive it themselves with their labor being rewarded at the end of the rehab with a truck worth more than they have into it.
Unless you are hiding a great deal more mechanical talent than you are letting on so far, I would strongly recommend staying pretty close to home modifications wise. So that would be a no, in my opinion, on the 6.2L swap notion.
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Thank you sir. Yeah, so first, the 6.2 would not be a swap that I would do. haha. I can fix simple things, but am way out of my league on stuff like that. And yes, you are correct, my truck is actually in great shape for over 200k miles. Even the garage told me that if they were me, considering the shape it's in, they would just replace it and drive it for another 200k. The other side is to replace it and sell it. My biggest concern is that I have done nothing to it as far as maintenance/repair with the exception of the typical oil changes, and window regulators, gas going in slow, basic stuff I can do myself. But what happens at this mileage when serious issues happen with electrical, transmission, etc. I would hate to put 4-5k into an engine, and then have it turn into a money pit over the next few years.....
Time for a professional evaluation bumper to bumper. Because it’s right on the edge IMO. You might do the engine and get another 100k without any major expenses. Or it could be the start of a chain of replacements. Transmission, suspension, brakes, HVAC... A lot of that is cheaper than payments when you do your own work, but when you’re paying a shop, it gets out of hand.
Exactly what I'm thinking Bill. I suppose I'll call today and get pricing on my options as regardless I need them to work on it and get it up and running. From there it's a matter of figuring out if I want a car payment again or not. lol Thanks for the input. It's good to see others with the same common sense trying to help me make up my mind. hahaha
I think we all can talk ourselves into just about anything as it pertains to what car/truck we really "need".
I have known for a long time that even with outside shops doing the heavy lifting or me, it is still cheaper for me to keep what I have. It happens my truck is pretty close to perfect for my daily needs, so I just fix (or have fixed) things as they crop up. My truck also happens to be in great shape, which helps at least my state of mind.
Recently, the new AT4 Yukon's really struck my fancy. It turns out they have equipment that is an actual upgrade to my needs (electronic limited slip diff), versus just bells and whistles and a new body style.
In the end, after reanalyzing what I already knew, I came to the conclusion the first year's depreciation would put a new reman in my truck (or pay for pretty much all the other major mechanical issues that could possibly crop up) and then I would have a number of trouble free (and depreciation free) years ahead of me. All the while with the new AT4, I would have the same depreciation number facing me the next year. That doesn't pain stop for quite a few years.
So for me, unless I get hit pretty good by somebody missing a stop sign, I think I will just fix what I have now.
I have known for a long time that even with outside shops doing the heavy lifting or me, it is still cheaper for me to keep what I have. It happens my truck is pretty close to perfect for my daily needs, so I just fix (or have fixed) things as they crop up. My truck also happens to be in great shape, which helps at least my state of mind.
Recently, the new AT4 Yukon's really struck my fancy. It turns out they have equipment that is an actual upgrade to my needs (electronic limited slip diff), versus just bells and whistles and a new body style.
In the end, after reanalyzing what I already knew, I came to the conclusion the first year's depreciation would put a new reman in my truck (or pay for pretty much all the other major mechanical issues that could possibly crop up) and then I would have a number of trouble free (and depreciation free) years ahead of me. All the while with the new AT4, I would have the same depreciation number facing me the next year. That doesn't pain stop for quite a few years.
So for me, unless I get hit pretty good by somebody missing a stop sign, I think I will just fix what I have now.
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As @Bill 1960 stated above, it probably makes sense to pay your shop $100 to give the truck a thorough inspection, and give you their assessment on what significant repairs 'might' be on the horizon. Better decisions are typically made when more information/data is available.
kbuskill
***CAUTION*** I do my own stunts!
@tights24
P0300 is a Random Misfire... not a hard/dedicated misfire.
That alone will cause the Stabilitrac and Traction Control lights to come on... which scares a lot of people into thinking there is more wrong/going on then there actually is.
P0455 is a Gross Leak on the EVAP system which is really no big deal as far as running is concerned.
I would start off simple.
When is the last time the spark plugs and wires were changed???
P0300 is a Random Misfire... not a hard/dedicated misfire.
That alone will cause the Stabilitrac and Traction Control lights to come on... which scares a lot of people into thinking there is more wrong/going on then there actually is.
P0455 is a Gross Leak on the EVAP system which is really no big deal as far as running is concerned.
I would start off simple.
When is the last time the spark plugs and wires were changed???
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I would have to disagree.
A P0300 is Random/Multiple misfire. An occasional misfire in random cylinders may or may not light up the Stabilitrack/TC errors, but a hard misfire in two cylinders will produce a P0300 and the ST/TC error. Actually a single cylinder hard misfire will also produce that ST/TC condition (kind of sorry I know that).
His mechanic has stated they tested the compression and he had two cylinders at zero compression and one very low. It would be nice if they had done a little more research on that front, but a P0300 and two cylinders not firing at all, certainly fits all the data provided so far.
He may have bad plugs and wires (and they very well could be responsible for the misfires) but again, given his explaination of how the symptoms manifested themselves as well as the compression test results, he probably should get to the bottom of the obvious stuff before starting to change plugs and wires.
At least, that is the way I see it.
This was certainly not a matter of it not running. I could barely drive it. When it was dropped off at the garage, it wouldn't run for them at all. So they started their digging and eventually found no compression on 2 cylinders and a third that was super low. He thinks it's the lifters(?) and the cam, but can't be sure there's not something else wrong until he digs into it. I suppose the risk is to have them dig into it and get so far into replacing parts with labor and parts cost that it would have been cheaper to just get a reman with a warranty and call it a day...
CaptainAmerica1
Full Access Member
Sounds like your afm lifters took a dump do an afm delete $2500ish if you have to pay someone to do it. Drive it till the rings or bearings die…
The mechanic can pull the valve covers and verify. If that’s not it, your rings are toast. I’d buy a used low mileage LMF ($1800ish plus R&R)and tune the afm out.
The mechanic can pull the valve covers and verify. If that’s not it, your rings are toast. I’d buy a used low mileage LMF ($1800ish plus R&R)and tune the afm out.
kbuskill
***CAUTION*** I do my own stunts!
I get what your saying and would normally agree BUT...
If you have two completely dead cylinders, with zero compression, why wouldn't you have two codes for hard misfires on those two cylinders instead of random misfires?
I'm not saying the shop was lying but it takes longer to run a compression check on all eight cylinders than it does to pull both valve covers and watch the rockers to see if they are all moving. Seems like if they were already that far in wouldn't that be the next logical step in order to give the customer a definitive answer?
I can literally have my drivers side valve cover off in 2 minutes. Pull the 5 bolts that hold the coil pack brackets and lay them off to the side and pull the 4 bolts in the valve cover and your in.
I guess I am just naturally skeptical of mechanics shops. I have seen way to many people taken advantage of because they didn't know any better.
With 206k miles on this engine, with the way some of these LS engines like to drink oil, if it hasn't had the plugs changed in a long time they could definitely be fouling out and causing random misfires.
Any way, it was just a suggestion, if you like it try it, if not throw it away... lol
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I don’t know the criteria GM uses for when they throw a P0300 versus a P030x, code when multiple cylinders are misfiring, perhaps he has enough other less frequent cylinder misses that the ECU can’t decide, IDK, but I know it happens (the P0300 versus multiple P030x codes). It would be pretty helpful to see the cylinder misfire count history with their scan tool.
I don’t disagree with the skepticism, frankly the diagnosis seems a little sparse, especially when a decision between a reman and open ended major mechanical work are the stated options. I have never worked in a shop, but I have done a lot of compression/leak down tests and if I found a few cylinders with zero compression, I would likely want to at least attempt to isolate the problem to the top or bottom end before “tearing into it”.
On the other hand, maybe the techs did that and didn’t feel compelled to go into detail. No compression in one or more cylinders definitely points to something ominous if it is real, I think I would want a little more detail before making an expensive decision.
To the OP, even if you trust these guys implicitly, perhaps you could ask for a little more detail on the testing they did to isolate the zero compression issue (there can be more than one root cause to zero compression). Also, tear down doesn’t take a lot of labor to get to the point of being able to see pretty far into things. You certainly don’t have to rack up “rebuild hours” to get a pretty good idea what you are looking at damage wise.
I would think a collapsed lifter would not lead to no compression, most likely as they usually fail in the “short” configuration and won’t open the valves. I’m thinking it’s a broken spring. Had it happen on our 2007 Denali at about 140K. Ran like it was an old Johnny Popper. Got lucky that it didn’t take out a piston.
Did the shop pull the valve cover and look at anything or just pull a plug and check compression?
Did the shop pull the valve cover and look at anything or just pull a plug and check compression?
kbuskill
***CAUTION*** I do my own stunts!
This would definitely make sense as he was driving it when all of a sudden he had the issue. If the lifters collapsed you would think he would have mentioned the awful tapping/clattering sound that would have likely accompanied it.
Thank you all for the replies/suggestions. To try to answer some of them:
1. They went into detail about which cylinder but frankly I forgot.
2. I was doing roughly 75mph when this happened on the highway. First thing was a noticeable semi-loss of power and slight shuddering. I honestly thought it was a tire going down as it was a very quick rapping as if I was down on the valve stem at that speed. I started to slow down and the light popped up. As luck would have it I tried to get to the first exit, just a half mile away, and of course cars were lined up back onto the highway. I got into line and it started running super rough. I pulled off, put it into neutral and it leveled off fine. Decided to put it back into drive, put on the 4 ways, and drive through the grass to a good spot down off the exit to park it.
3. They still have not called to tell me pricing, but they are going to give me pricing to open things up and potentially fix what they think it may be, and also pricing for a reman. I also asked them for pricing for a once over to address any other major expenses that may come up.
I had the same thing on my Yukon, but I think broken valve springs on more than one cylinder at the same time might be a low probability. And then there is the "low compression" on the third cylinder.
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