Stumble At Idel

[D&SYukonDenali]

The truck is going in for some things next week, one being it stumbles at idle; enough where it shakes the truck every once and awhile at a stop. Also, on a cold start, but moderate temperatures (45 - 60 F) I push on the gas and it hesitates a little bit. To me, it feels like it's missing or has a foul plug, but the truck has less then 10,000 miles on it.

 

Though I going to have them check this out, is it normal with the 6.2 Lt or anyone else expereince this? Could this be part of the GM restrictions (torque management / abuse mode) on the truck?

 

EDIT: Can an admin fix my spelling error in the title; I have head-up-*ss syndrome today

[trever1t]

I can't answer about the 6.2L (congrats btw) but both my previous and current truck had a little stumble when in park r stopped in D. The idle is set pretty low from the facory, bumping it up a 100rpms would probably take care of it.

[Bostonsfavson]

How often is once in a while Dan? I have 17K miles on my truck and I can count on one hand the number of times the RPMs have dipped low enough that it's caused the truck to feel like it might stall. The automatic idle control should kick in at that point and bump the idle up, which is also what causes the fluctuations in RPM when you're just sitting in your truck. What type of gas are you running? As far as the hesitation you're feeling, that seems like a pretty cut and dry case of abuse management software.

[D&SYukonDenali]

Happens almost everyday. And the truck has only ever seen BP premium fuel (I beleive it's 93 octane). the abuse management has to be set fairly low since I really don't get on the gas at take-off.

 

If they come back and say it's all normal, might just have to get the Blackbear tune.

[D&SYukonDenali]

OK - Dealer said they felt the stumble, but said it was normal for these truck (something with the cams).

 

Now this is my first truck in 8 years (previous were '68 Chevy C-10, '72 International, '75 Chevy, '86 Chevy), so being that far removed I don't know if I'm just use to cars and this is normal for trucks, just something recent to increase MPG by turning down the idle, or is it not normal? So, for those that have both a car and the turck currently, can you tell the difference in the idle between the two?

[ColoradoSkiCountry]

Every vehicle I have owned, domestic or foreign has done this

[D&SYukonDenali]

Every vehicle I have owned, domestic or foreign has done this

 

The only other time I remember feeling this type of stumble is when my previous car needed a software upgrade.

 

Just more ammo to convince me to get the Blackbear tune once the EFI Live handheld is available.

[Jje121]

I noticed my truck has a slight stumble when it is in D and I am at a stop. I didn't know if it was normal either. I thought maybe I needeed some new plugs and wires or something. I don't have the 6.2, I have a sierra with the 4.8.

[Bostonsfavson]

OK - Dealer said they felt the stumble, but said it was normal for these truck (something with the cams).

 

Now this is my first truck in 8 years (previous were '68 Chevy C-10, '72 International, '75 Chevy, '86 Chevy), so being that far removed I don't know if I'm just use to cars and this is normal for trucks, just something recent to increase MPG by turning down the idle, or is it not normal? So, for those that have both a car and the turck currently, can you tell the difference in the idle between the two?

 

 

There is a difference in the idling behavior between the Denali and the 3er, but it's not huge. The 3 purrs like a kitten at a steady RPM, while the Denali does fluctuate a bit. I've chalked it up to not only the automatic idle control, but also the fact that it's a big ol' pushrod 6.2L engine. Seems about par for the course I think.

[redvett]

Happens almost everyday. And the truck has only ever seen BP premium fuel (I beleive it's 93 octane). the abuse management has to be set fairly low since I really don't get on the gas at take-off.

 

If they come back and say it's all normal, might just have to get the Blackbear tune.

 

Your wasting your money and causing extra carbon build up with 93 octane because the high octane retards flame travel or spark knock.

[Prog53]

Mine does it to but almost too the point where my truck will die out and come way back up. sometimes even dieing completely. i figured if im stopped just rev it up 100-200 rpms and it stops it. if i could figure out how to set that at default it would be perfect.

 

any idea how to do that?

[redvett]

Mine does it to but almost too the point where my truck will die out and come way back up. sometimes even dieing completely. i figured if im stopped just rev it up 100-200 rpms and it stops it. if i could figure out how to set that at default it would be perfect.

 

any idea how to do that?

 

Since your Sig. is absent of M&Y we have not idea what your driving but you may want to try cleaning your IAC passages if it has TBI or SFI.

[Prog53]

Im sorry 1988 K1500 Z71 350 automatic

[BigJayDogg3]

Happens almost everyday. And the truck has only ever seen BP premium fuel (I beleive it's 93 octane). the abuse management has to be set fairly low since I really don't get on the gas at take-off.

 

If they come back and say it's all normal, might just have to get the Blackbear tune.

 

Your wasting your money and causing extra carbon build up with 93 octane because the high octane retards flame travel or spark knock.

 

 

Don't you have to run premium in the 6.2?

[Bostonsfavson]

Happens almost everyday. And the truck has only ever seen BP premium fuel (I beleive it's 93 octane). the abuse management has to be set fairly low since I really don't get on the gas at take-off.

 

If they come back and say it's all normal, might just have to get the Blackbear tune.

 

Your wasting your money and causing extra carbon build up with 93 octane because the high octane retards flame travel or spark knock.

 

 

 

GM actually recommends running premium (93 octane) fuel in the L92 6.2L engine. So he's doing the right thing.