Ba turbo idle stutter rev up?

[jas98]

Ba xr6t 

 

Been having an issue for a few weeks when randomly at idle car mite be idleing and all sudden for a split second missfired but at same time it revs up quickly and is all good ...this all happens within like 1-1.5 seconds. 

.other times when it does this it does same but besides revung up for a second it revs right up and missfired/stumbles etc till turn car off and on again . 

 

 

Mite do this a few times over say 4 days then comes good for a week or so and then does it again. 

 

When driving car it's fine...dosnet do it or miss etc only seems to be at idle 

 

 

 

Codes I get are related to excessive rpm ..and maximum speed reached codes

 

 

Also I have tried a different throttle body and TPS.  Which it came good for a few days after that. 

 

There is no intake leaks etc literally covered everything besides maybe coils? But surely it would do it while driving aswell bot just idleing? 

 

Also thinking possibly wireing issue to throttle body but again why only when idleing? 

[k31th]

if it's so intermittent like that, it does sound like an electrical/wiring issue...

[benjam]

Hey jas98, I had a similar issue about 18 months ago with idle revving up and then down to normal when putting the clutch in before stopping. You did say you have no intake leaks, but it was the intake manifold gasket for me. I could also hear a slight air sucking noise towards the front passenger side of the engine compared to other areas along the manifold. The ECU controls the idle and was compenstatng for the extra air when the engine speed wound down to idle. It was happening both when engine was just a bit warmed up or after a normal drive too.

 

I was able to change the gasket myself (long but not overly difficult) and also gave the throttle body and plenum a good clean. All good immediately afterwards. I had already had the spark plugs and coils changed for a different issue (lack of spark at WOT) about 6 months before, so it wasn't that causing the idle issue. Cheers, Ben.

Edited 28/06/25 02:19 AM by benjam

[jas98]

Hey thanks. I did check all this but wasn't the issue.

 

The issue was a weired one ....after all the crap I swapped I decided to remove the pcm 

..unplug the connectors and reseat the connectors/plugs. Bolt pcm back and also I added 2 new earths from battery. One to engine and one to chassis. 

 

In unsure which of the three had an affect but it's been 2 weeks since and it hasn't done the issue since. 

 

The earths are just a temp solution as I'm going on a long trip in a couple days and honestly do not want to disturb the car as it's being good since I done this stuff. 

 

 

So it either ra bad ground from chassis to engine....even though the strap looks good etc and clean and connections are clean or it was the one from battery to chassis ..but it's been replaced 6 months back and is clean 

 

 

Orr it was a bad connection at PCM 

 

 

Either way it may or may not show it's ugly side again. 

 

 

 

Anyone who has similar issues if suggest reseating the plugs on PCM anyway a d checking earths

[xr6tForMe]

Great that you got it sorted and nice that you have let people know what did it for you.