Very slight misfires

[Mp64]

I've had my VE SS for about 2 months now, and about 2 weeks ago I noticed a bit of stuttering while it's idling. It's not noticeable when the engine is cold, quite noticeable when it's been running for 10-15 mins, then barely noticeable when engine has been running for about 30.

I've gone ahead and replaced the spark plugs and leads since they were due soon anyway, but no change to the stuttering.

Any ideas what the next biggest culprit would be? It's extremely light stuttering/misfires, more by sound rather than feel. But I'd ideally want to get it sorted in case it potentially leads to something else.

My engine is an L77 auto if that helps. No mods to the engine yet

 

[krusing]

Maybe best to get is scanned,
At least it may give you an indication where to start to look,
Being it will historicise the faults.
As not all faults will activate the MIL.

Where in "Victoria" are you ?
As there maybe a JC Member close to you that maybe able to assist/help.

 

[Banjo79]

My L77 has very slight hiccups when warm. 98 amplifies them, 95 or e85 almost eliminates them. It's been tuned for 98 and e85 twice and has always behaved the same. I've done leads, plugs and injectors over the years and none made a difference.

 

[krusing]

I did read Plugs and Plug Gap is very critical for L77's,
So when I did my Plugs and Leads,
I checked the resistance of all the leads approx. 800 > 900 ohms,
and the plug gaps, which I found were way out on the New Plugs.
My L77 also have a bit of a hiccup now and then idling, but I have got use to it.

 

[Mp64]

I did read Plugs and Plug Gap is very critical for L77's,
So when I did my Plugs and Leads,
I checked the resistance of all the leads approx. 800 > 900 ohms,
and the plug gaps, which I found were way out on the New Plugs.
My L77 also have a bit of a hiccup now and then idling, but I have go use to it.

Hmm if it gets any worse I will buy a gap tool and check the plugs

I do have a cheap scan tool which doesn't throw any codes

 

[krusing]

The Gap tool I have is a Coin Gap Tool from Supercheap,
I think I paid $1, or there abouts at the time.
https://www.supercheapauto.com.au/p/sca-sca-spark-plug-gap-gauge-coin/344862.html#q=gap+tool&lang=en_AU&start=1

Hint: Can also be used as a stubby opener, when your re-gapping the plugs !

 

[krusing]

Hmm if it gets any worse I will buy a gap tool and check the plugs

I do have a cheap scan tool which doesn't throw any codes

The professional scan tools can check cylinder/plug misfires in the ECM's history,
as it may not cause the MIL to activate.

 

[Freddy Kruger]

Mine has a slight miss at idle too. I think it's feature from GM.

I always use 98 but i might top up with 95 next time and see if i notice any difference.

 

[MYVESSV8]

there is a big thread on here regarding fuel and tuned V8's, have a read it may help, has alot to do with 98, E85, ethanol fuels etc

 

[TAS1981]

Could be a dirty or failing MAF.

A tech 2 scan is a good idea anyway. I was trying to diagnose a slight miss at idle, a check engine light and another small electrical gremlin so I had this yesterday.
It picked up rear wheel speed sensor issues in the past (now not present), MAF low and out of range readings and clutch pedal B circuit problem.

A careful spray of contact cleaner on the MAF cleared the check engine code and resolved the slightly lumpy idle. I have a VCM OTR so oil deposits can get on the MAF and degrade it over time.