intermittent shudder at idle - carton reward

[keleher]

If anyone can solve this I will have a carton of cold ones delivered to your door as it is doing my head in and cost me a fair bit to not solve it. Car has a very intermittent shudder like a D.D.D....D.D.D....at idle where the whole cab gets a jolt through it but I can't seem to make it happen when I have it plugged into techstream or at various mechanics or diesel specialists so they tell me she runs great. Some details:

- It started a few months ago and a swear the shudder is getting more intense
- It only happens while stationary and my foot is on the brake, if i take my foot off the brake it subsides and if i tap the accelerator or let the clutch pinch slightly it goes away. I have tested all vacuum lines and brake booster with a vacuum gun and no leaks.
- Revs don't drop
- It mostly happens after coming off the freeway but has done it in start stop heavy traffic
- It only happens when at operating temp and been driven for at least 20 mins or so
- It doesn't do it in cool weather (<15 °C) but seems to happen more frequently the warmer it is.
- No codes
- All readings in techsteam are in spec but I cant get it to play up while connected
- Injectors are all under +/-1
- Runs great when moving, no power loss
- No smoke or knock

Things I've done to no avail:
SCV
Timing belt
fuel and air filter
fuel leak test
cleaned maf
cleaned egr again
engine mounts
Serpentine belt, pulleys, tensioner
harmonic balance
alternator

Anyone got any ideas?

[fracturedranga]

Thrust bearing maybe? Does it happen when the clutch is engaged? What about when you put it in neutral and release the clutch?

[keleher]

Had a new clutch and thrust bearing put in the other weak when rear main seal went. Does it more so when the clutch is depressed but doesn't seem to make a difference when I put it out of gear and release the pedal

[TOYZX]

Spigot bearing? Should have been done with the clutch but ya never know. Input shaft bearing?

Sent from my SM-N920I using Tapatalk

[keleher]

Yeh had the spigot done also. If it was a bearing wouldn't it be rough all the time or make noise?

[fracturedranga]

Not gearbox bearings, they get different loads on them depending on whether the clutch is engaged or not and in gear under load, the spigot bush is pretty easy to damage when reinstalling the gearbox and can make intermittent noises although in my experience they make more of a squeal than a shudder. Shudders and noises are pretty hard to diagnose without actually hearing it in person, maybe try and get some video with audio when I happens, might help

[EKJ]

Dual mass flywheel are one option not listed here, that can make a problem like u experience.

[TOYZX]

Pretty sure the lix has never had a dual mass flywheel. That question got absolutely killed in the cluth thread.

Sent from my SM-N920I using Tapatalk

[martynvella]

Wow, this is a no lose situation, for the punter, it could cost the OP dollars listening to the suggestions.
Try the noise suppression capacitor in the wiper motor.

OK I know nobody likes a smart arse but you can see what I mean.(I'm bored again)

[EASTCOAST]

sounds like a rubber bush the way you describe how and when it happen,

Gear box mount or a hose/cable in the engine bay contacting the body ??

[keleher]

I don't think it has anything to do with transfer or clutch it doesn't matter if it is in or out it does it but it only does it at idle when stopped and out of gear. In gear it drives fine and on the dino didnt miss a beat. I'm guessing it is sensor/electrical/Ecu related given it happens when I press the brakes while stopped and it feels like a miss. Hoping to narrow down an area to start looking.

Mounts are all fine

[hippo]

sound like harmonic balance. either the pin is broken or lose bolt which cause engine shudder at certain speed and idle

[cooganstein]

Idle speed to low perhaps. So when the ac cycles it may get close to stalling/shudder

[Flippa]

I had a similar thing with my auto Prado 1KD. Different I know but may be worth a shot. I replaced heaps of stuff but ended up finding the bracket on the aftermarket exhaust from the bottom of the dump pipe to the bell housing was broken allowing the exhaust to get a swing up at idle. I fixed it and never had the drama again. I really didn't believe it would have caused it but it did?

[keleher]

sound like harmonic balance. either the pin is broken or lose bolt which cause engine shudder at certain speed and idle

Done it before and after I replaced the harmonic balance and bolt

Idle speed to low perhaps. So when the ac cycles it may get close to stalling/shudder

The revs sit an about 750 when it happens I didnt think you could adjust this on these ones?

I had a similar thing with my auto Prado 1KD. Different I know but may be worth a shot. I replaced heaps of stuff but ended up finding the bracket on the aftermarket exhaust from the bottom of the dump pipe to the bell housing was broken allowing the exhaust to get a swing up at idle. I fixed it and never had the drama again. I really didn't believe it would have caused it but it did?

Gone over the exhaust and done up every bolt as hard as I could but didn't change

it doesn't make any noise at all and its not a vibration the engine feels like it is bouncing up and down and I'm pretty sure it is visible from the outside. Doesn't matter if the a/c is on or off or if the clutch is in or out (but not in gear) it still does it. The only pattern i have noticed is in cool weather <15 it runs fine but when it is warmer it happens, usually when I come off the freeway or pull into a car park.
The longer I leave my foot on the brake the more intense the shudder/bounce gets when it happens. when I take my foot off the brake it goes, sometimes it comes back when I touch the brake straight away others it doesn't.
Could it be something to do with the vac pump? Tested all the lines there is no leaks, the solenoid valves are working and at idle its pulling what it should.

[cooganstein]

How olds the fuel filter?

[wyworrie]

A similar thing occurred to me years ago with a ford - could be worth a look. It turned out to be the aircon compressor bearing that eventually broke and threw the belt off. Ford had looked at it so many times and of course it never did it in the workshop.

Good luck

[hippo]

check the external belt pulley system, maybe is loose. if not check the timing belt hydraulic tensioner and idler bearing.

[Qwerty]

Idle speed to low perhaps. So when the ac cycles it may get close to stalling/shudder

Ironically the oppposite is true, engine rpm comes up a bit when AC is on. at least in my 1GRFE it does.

have analysed it a lot when looking at my Alternator output issues at Idle (now have an idle up switch).

[keleher]

How olds the fuel filter?

It had about 8000 on it but changing it and the scv made no difference.

A similar thing occurred to me years ago with a ford - could be worth a look. It turned out to be the aircon compressor bearing that eventually broke and threw the belt off. Ford had looked at it so many times and of course it never did it in the workshop.

Good luck

I've had the belt off and the aircon bering spins smooth as silk with no noise.

check the external belt pulley system, maybe is loose. if not check the timing belt hydraulic tensioner and idler bearing.

Replaced the belt,pulleys and tensioner on serpentine belt and timing belt. Vibration is a touch less but the shudder/ bounce still happens.

Sometimes it is real faint, mechanic thinks I'm imagining things, others it's like the engine is going to smash the bonnet open but that doesn't happen when I got the mechanic there.

Anyone know if a swirl valve stuck open would cause this?

It only happens when I touch the brake so surly it's something to do with the vaccume? Or does the brake feed into the Ecu somehow?