Random Stall/shudder on idle

[sxc_sound]

Been happening for a few weeks now. Stalled 3 times within 1 hour. then nothing for a week. then started shuttering and a few random stalls in between. Does it mostly when the motor is warmed up. ONLY ever on idle. so sitting at traffic lights, it will shudder, revs drop riiiiight down then it will pick itself up and go back to normal, other times it wont recover and just stall.


Leads/plugs were replaced 8 months~ ago. fuel filter/air filter/ oil filter/oil all replaced last service (6 months or so ago)



i so far have a list of the cause being from

EGR valve?
A faulty coil pack
Dodgy fuel? even tho i get it from different places


Im stumped on this one, any help is much appreciated.

[som]

possible throttle position sensor which would show on a diagnostic check (as may other possible cause of your problem) Anyway if it is a tps they're cheap and simple to replace.I reckon I'd go the diagnostic check first.

[Cameron P]

+1 for throttle position sensor.

if it was dodgy fuel it would miss whilst driving right

[GEN3RATD]

if it was dodgy fuel it would miss whilst driving right

this is correct

[Cameron P]

this is correct

i wasnt asking i was telling hahaha

[sxc_sound]

googling around a few people mention the Crank Angle Sensor can play up when hot? not sure on that either

[Cameron P]

there common so you might aswell start there and even if it doesnt fix the issue it will save you hassle in the future

[sxc_sound]

Ok just went outside and did a diagnostic test on it. i got the codes

12 - Satisfactory Operation
46 - Crank Angle reference signal (engine will not start)
47 - Crank angle reference signal (no signal)
12 - Satisfactory Operation

Then it started repeating again as it does.


SO i believe im now off to bursons to get a CAS

[Brett_jjj]

Id definitely be replacing the CAS.Id try to get a genuine holden CAS if you can,they may be more expensive ,but they seem to last a lot longer.Ive seen plently of the cheaper ones fail just a couple of years later or even less,so it can work out more expensive in the long run if you get a dodgey one that only lasts a couple of years..

[sxc_sound]

I bought a new CAS and a harmonic balancer puller kit. Just have to work out how to get the main nut off first. Im thinking sit a long breaker bar on the nut and againts the chassis and crank the motor real quick to break the seal

[Cameron P]

why not use some muscle lol. your idea is a little crazy im my opinion o.O

[clubsport_replica]

yeh you could try it that way, do you have a rattle gun? if u want to do it that way id check to see if the motor is going to spin way to undo the nut with where u have placed the breaker bar otherwise snapp bolt. also take the fuel pump fuse out and make sure the engine wont start on you.

i had a similar problem in my vt ss with the shudder/stalling when i pulled up turned out faulty earth lead engine to chassis and faulty battery and alternator.

[sxc_sound]

Nah i should be good with earthing, im a full time audio installer. 2 runs of 1/0 gauge wire to the Alt/batt/chassis and the positive on the Alt lol

[clubsport_replica]

the wires are good n all but have u checked the resistance between all of these.

[mbvp73]

Hey sxc_sound

Did changing the CAS fix your situation? I am having exactly the same problem atm. I had a CAS go on my old VP but with that the car would just die all the time, my VT is running great EXCEPT at the lights with the auto in DRIVE its starts going a bit silly. If it starts doing it while I'm driving or dying then yeah, it could be the CAS. Nothing a squirt of water wont fix.....albeit temporarily.

[sus_038]

I had the same prob, i replaced the CAS and cam angle sensor... never had a problem since

[mbvp73]

Hey sus_038

Hmm, seems like maybe my CAS is dying. I know where they are on a VP but whereabouts is it in the Ecotec engine? Somewhere near the HB I gather but right side/left side of the HB??