Pma93

im having issues with my LS1.. its got a mild cam upgrade, exhaust system and a mafless tune and has a t350 race gearbox.

awhile ago i would just be driving along and when i backed my foot off accelerator (to brake/slow down) it would on occasion cut out - as if te key had cycled off, and usually would start up and run fine straight away.

this got worse and when the engine was cold it would try to cut out under normal driving conditions, but would kind of save it self from completely stalling - so it would cut out but quickly cut back in if that makes sence. it did this a couple of time until the engine warmed up (not sure if temp actually is related to fault)

for awhile if i idled it for 5-10 mins each morning before work i wouldnt experience any fault. however after some period of time it has now begun to cut out when idling. It might last maybe 2 minutes then will just cut out.
it will start again first shot and run fine, it will the cut out once again but after a few shots the engine starts but runs noticeably worse (rpm drops off, sounds like its missing though might just be low revs)

ive been trying to get my head around this issue for a few months now and cant seem to come up with anything.

i was hoping the may be someone on this site that could of experienced similar symptoms or would be able to lead me in the right direction.
thankyou.

flattusmaximus78

iTrader: (1)

Scan for codes and report back.

Burken01

iTrader: (88)

Is your check engine light on?


Pull a spark plug and see if its fouled out..

My wife's car was doing similar things and it had no SES lights at all, I pulled some plugs and they were fouled out..

Changed them and they fixed it..

Also a mafless tune? SD tune? Why did you get rid of the maf just curious

Pma93

just recently had all plugs replaced, (routine servicing) so I wouldn't of thought theyd be fouled as of yet haven't been doing a lot of driving yet.
had a scanner on it this arvo and has codes coming up but no engine lights on dash.
maf-less, well I bought the car and it was already maffless tuned, have hd car re-tuned since but I don't feel like theres any need to put one back on
In australia a lot of people seem to like mafless tuning.

had codes for maf sensor (car has mafless tune)
evap emission purge solenoid circuit
vehicle speed sensor (also been tuned out of computer)

had a play around today, when codes came up, fairly confident we diagnosed that the evap puge solenoid was stuck.

revved up engine with solenoid on and with connector plugged in and un plugged, engine wanted to die. or did.
pulled solenoid out, revved engine and it DID NOT want to stall - ran fine.

is it possible this whole time that the evap solenoid was sticking until the engine warmed up and causing stalling/cutting out?
ran engine without it installed and seemed ok??

F47CV8

​​​​​Im experiencing the same thing, my LS3 is randomly cutting out at any given time..!!!
I've done an LS3 swap from an LS1 but kept all LS1 accessories n cable driven n ecu, so nothing much has been tampered with...
Was running fine for 22,000km, but now randomly cutting out...

Did you end up figuring out your problem..?

BigBoyWS6

Thats exacty what the Crankshaft Position Sensor does as its failing. I chased that same exact issue for about a week trying to find what the hell it could be......then someone told me to swap it out even though there's no code and it still works perfectly most of the time.

Our PCMs do NOT give us codes for a lot of items that are starting to fail, kind of like the old cars with idiot lights.......you get the code when its too late and you're stuck and it will not start up again.