Hey guys

Tried searching the site and only found a discussion from 12 years ago about a g20 van I think lol. So signed up to ask this. (Oh and a side note, I ain't no mechanic and I don't pretend to be, so if I screw up terms my apologies.. I can do water pumps, starters etc.. but beyond that I toss in my hat)

I have a 2000 suburban 2500 6.0L gas. The shop I take it to (family friend, but not a chevy specific place) says that my rollers have mushroomed against the cam and the engine is toast. It misses under load when warm, but not 100% of the time. In a 2.5hr drive on the highway I'd say I would have a good half hour of it missing.

Guys I work with think this is kind of suspect, one said if it was a mechanical issue as they claim I would be seeing the issue all the time not just under load. They both think something else could be or should be the issue. One recommended checking the plugs/wires and see if that does anything and another said to check the distributor. Also I have been changing out sensors etc and after I put in a new MAF sensor this issue really took off, which is suspect to me.. but my weak $100 scanner can't pick up any codes... could this missing be a bad MAF sensor? My MAP sensor needs to be replaced too, could that do it? (I have new 02 sensors etc, been kinda building this for my hunting/camping rig). Is there an easy test to prove it is the mushroomed issue?

Now if it is the Mushroomed lifter, the shop said the engine is a write off... I'm just curious would a new set of heads do the trick and pull the cam to help get the lifter out? Or what is the general consensus of buying junkyard engines around 140k kilometers (the truck has 320k kilometers on it and I can source a new engine/tranny combo for 5k installed from a local wrecker verse the 10-13k for rebuilt ones from ATK/others).

Any rate what's the advice? Throw money at this engine assuming it isn't a mushroomed lifter against the cam? Buy a junkyard one? Replace the heads only?

Kind of at a impasse, i have enough cash to fix it.. but not to waste.. so looking for help
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thanks kindly
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did they re move the valve cover and watch the valve train? What did they do to confirm a lifter problem?
if its missing underload there should be misfire codes?
i agree with your friend...lifter/cam problem should be all the time.

I have seen worn cam lobes for the 6L. but misfire codes set and the miss is all the time. teardown and inspection required to see the damage. if bad enough there is metal in the oil pan.
put the old maf in.
hard to say without a test drive...
tcc shudder is one option?
cat starting to clog?

 

I won't lie, we took it in cause we guessed it was a clogged cat.. We did have some lean running codes and kind of suspected the cat had clogged. I don't know if he took the valve covers off to check.. sort of assumed he would before giving such a disastrous quote.

I'll try to take her for a spin and keep a scanner on her and see if anything comes up. The old MAF I returned for the core refund. But I guess I'll grab another and see what it does >.< if I can find a receipt maybe I'll see if lordco will honor it if it is defective lol. I have seen no metal in the oil either and when I got the oil change done was not told of any either...

Starting to seem like a lot of voices are saying the problem may be something else.. I don't mean to be rude, but could I ask your experience boss man? Blah that sounds bad just asking >.< I just mean to say someone who has been a gm tech for 30 years.. has a bit more weight then a 19yr old high-school student. As you're a super mod I suspect you have some clout. Again I know it sounds arrogant I don't mean to be.

 

I fully agree with Tech2
Unless you have X ray vision tear down is required for valvetrain issues and as Tech2 said once valve train issues start, they are forever not part time.
Misfires will set a code for the cylinder missing and trigger a flashing CEL.
MAP can go out of range but not set a code. I chased it on my 5.3, fortunately my scan tool has 2 MAP tests and mine was erratically failing one test but no hard code. Drove fine but lost 3-4 MPG
GM parts only for sensors. Aftermarket stuff is prone to be bad right out of the box.
If it starts missing after running fine for a while it's most likely an electrical or fuel problem. Cats do not plug / unplug.
Under load miss could be low fuel pressure once fuel pump heats up. Been there also.

 

Thanks guys

I'll pick up a new MAF tomorrow and see what happens and try to pursue easy fixes.. here's to hoping that it is not a mushroomed lifter.

ill try to remember to keep yall in the loop.
thanks again
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Well guys, thanks a million.

Put in a new MAF today (looked fundamentally different then the one I had put in (which had looked like what was in there))

Truck is running like a top now, I wish I could buy you two coffee. If you ever find yourself in Northern bc the offer is open.

I appreciate it a lot and from some random guy on the internet, you just saved me a lot of cash so lots of good karma for sure.

Thanks
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