Hi all,

Before we all say - search, I did search and looked through the 5pages that came up with the search result that includes the word - Shuddering, including clutches etc.

It seems to be a 'saturday problem' as such - in that It did the same thing last Saturday when I was leaving Townsville, and it did it today when I was coming home.

The problem:
At IDLE, the car will sometimes shudder - engine still spinning over.

It will not do it while decelerating / coming to a stop - but starts just as I am about to come to a complete stop.
It does it - Aircon on, or aircon off, wheels turned, wheels straight, in drive/park/Neautral.
Only once it starts doing it - I cant make it shudder.

Last Saturday, It was doing it with a full tank of fuel from Townsville - I thought I picked up some bad fuel there as when I returned to Mackay and filled up again, the problem went away (came back today - hence Saturday problems! lol!)

Car was lowered in Tsv - so nothing was needed to be touched in the engine - nothing was moved or adjusted under the bonnet (apart from the strut tops) - the engine was not touched.

I have inspected visually the following (from looking at searched threads)
- Spark plug leads, all are firmly attached
- Transmission fluid, level and colour is fine (Trans was flushed at 140thousand - at 150 now, so only 10thousand KMs since last flushed
- Engine oil, Still have it - only changed 1500km ago (before Townsville trip - the day before actually... by a trusted mechanic where I always get my car serviced)
- CVs - car was up on the hoist at work recently, and I walked around under it - no leaks or grease stains or anything. As part of the servicing that gets carried out at trusted mechanic - they degrease everything so I would see any fresh oil/grease/fluid leaks when it was on the hoist.
Car does not have an oil leak either.
- Air box and intake piping are all secured together firmly, no air leaks / gaps there.

Car is no longer boosted - I ran the 5W40 oil for the 1000km without blower to the 150thousand KM service where normal grade oil was put back in / thicker.

Car currently still has the highflow fuel pump in the tank as well - Didnt get my std pump back from the installers and havnt purchased a replacement std item - dont see the need to either currently. Fuel pressure Reg will do its thing along with the other sensors to make sure it doesnt overfuel.

I do not run E10 fuel in my car - refuse to use it, I run the car with Min 95Ron in it at all times as most servos here with 91 are all ethanol blended 91s.

I reset the TC every time I fill up (only ever fill it - never just put $15 in it so to speak) - TC is showing 40L used.
I have prolly used about 42L realistically - being its a 70odd Liter tank - that means that not too far short of 30L is still sloshing around in there.

Last week - when I filled up (back in Mackay after Tsv) the problem pretty much went away - until today.

I will be filling the tank again when I go out to a party later tonight.

What other places should I be looking for problems?
Have I pretty much covered everything?
Where else should I be looking?

All advice appreciated :)

Cheers

If you're talking about a rough/low uneven idle then the 2 things I couldn't see in your list were Throttle body clean and making sure the ISC motor was working.

Not sure why this would happen just as you are stopping unless it's a trans/torque convertor issue?

My TW has had occasionally a lowish rough idle but I don't have any driveability issues. Cleaning the Throttle body has helped. Only notice it in gear when completely stopped.

Well, I filled the car up last night - and the problem seems to have gone away for now...
This is an odd one for sure....

WIll get the mech at work to have a look at it tomorrow if he has time to.

The Saturday problem, seems to want to become more than just a Saturday issue.

Full tank (3/4 full anyhow - close enough) of juice in it, pulled into a parking spot at the shops - selected Park - Shudder / Shaking...

Shut it down and when into the chemist to get my perscription (wasnt in the mood to look over the car in the rain..) came back 5mins later fired over and was running without issue.
(the other weekend when it did it - when I restarted the car, it continued to shudder / shake at idle)

Odd thought - as its been very wet up here of late - and the problem first presented after hurtling up the highway to Townsville through roads that in places - resembled rivers... I could have water ingres somewhere..
That would more likely create a constant problem though wouldnt it?

Car has 152,000 km on the clock as well if that makes any difference.

Mine does the same, my guess and good be the same problem as mine could be the engine/tranny mounts.
The lowering most likely induced a problem that was likely to be known later.
I know the mount that is near the firewall in mine is starting to sag and suspect the drivers side will follow soon.

Does yours sometime shake and splutter along and then sometimes its fine and runs without drama or issue Grelise?

Might ask favours to the mechanic at work again tomorrow (if I go in - im still dying from this cold... yeah yeah... i know - I should harden up a bit :P) and get him to have a quick looksie at it for me :)

mine does a similar thing to what you have described and i am 90% positive its the engine mounts, my drivers side one is shot and i am yet to have a proper inspection of the rest and if it isn't the engine mounts i presume it has something to do with the torque converted like mentioned above..

The car is still doing its little shuddering trick occasioally unfortunately.

Had an inspection of my engine mounts VS another TL Magna here in Mackay - which has had the drivers side engine mount replaced *VERY* recently.
They appear identical visually extenerally - however I would assume that if they where damaged - the bits that I cant see - would be the bits that are showing wear / age / fatigue?

Is there a way to inspect engine mounts without first removing them - any tests that can be performed?

All other mounts appear fine as well.

One thing I have noticed, it seems to pop up most, when doing applying more than normal / average brake force, not HARD emergency braking - the type where you approach a set of traffic lights and they change, and with not traffic behind you you can stop at the line without issue - hard braking.

When it does happen, it will continue while stationary (D or N makes no difference) - foot on brake only / hand brake applied / just sitting there with no brakes applied.

Car still idles at the same speed as when it is not shuddering - itl spin at approx 500rpm in Drive at normal operating temperature.

When accelerating, the shakes through the car increase and decrease slightly as revs rise and fall as the trans shifts gears. Shortly after a constant speed has been reaching and is being maintained the shudder / shake will start to dissapear slowly until its gone completely.

I need to drive this car 1000 km next saturday to Bris / Gold Coast / Towoomba, so im starting to get nerveous that there is a big issue at play.

Suggestions / advise appreciated with thanks :)

EDIT - its now doing it with a full tank of juice as well, so I guess fuel levels could be ruled out now?
Also - makes no difference as to if it has 91/95 or 98 RON in the tank - it can / does do it on each fuel.

If you're talking about a rough/low uneven idle then the 2 things I couldn't see in your list were Throttle body clean and making sure the ISC motor was working.

Not sure why this would happen just as you are stopping unless it's a trans/torque convertor issue?

My TW has had occasionally a lowish rough idle but I don't have any driveability issues. Cleaning the Throttle body has helped. Only notice it in gear when completely stopped.

Sorry - i completely missed your reply, I saw it but didnt mentally process it after reading it.

I havnt inspected the TB - but it could be highly likely its gunked up after the blower and running very rich tune for a while.
It has - As Far As I Know - never been cleaned before either (I have never done it)

AFAIK - the ISC is working correctly, when I flick the AC on / off , turn the wheel while stationary - can see the revs pick up accordingly to the conditions.

Will get the TB looked at too

The car is still doing its little shuddering trick occasioally unfortunately.

Had an inspection of my engine mounts VS another TL Magna here in Mackay - which has had the drivers side engine mount replaced *VERY* recently.
They appear identical visually extenerally - however I would assume that if they where damaged - the bits that I cant see - would be the bits that are showing wear / age / fatigue?

Is there a way to inspect engine mounts without first removing them - any tests that can be performed?

All other mounts appear fine as well.

One thing I have noticed, it seems to pop up most, when doing applying more than normal / average brake force, not HARD emergency braking - the type where you approach a set of traffic lights and they change, and with not traffic behind you you can stop at the line without issue - hard braking.

When it does happen, it will continue while stationary (D or N makes no difference) - foot on brake only / hand brake applied / just sitting there with no brakes applied.

Car still idles at the same speed as when it is not shuddering - itl spin at approx 500rpm in Drive at normal operating temperature.

When accelerating, the shakes through the car increase and decrease slightly as revs rise and fall as the trans shifts gears. Shortly after a constant speed has been reaching and is being maintained the shudder / shake will start to dissapear slowly until its gone completely.

I need to drive this car 1000 km next saturday to Bris / Gold Coast / Towoomba, so im starting to get nerveous that there is a big issue at play.

Suggestions / advise appreciated with thanks :)

EDIT - its now doing it with a full tank of juice as well, so I guess fuel levels could be ruled out now?
Also - makes no difference as to if it has 91/95 or 98 RON in the tank - it can / does do it on each fuel.

Maybe a long shot but i wonder if you may have a faulty brake booster. They run on manifold vacuum, I'm thinking if there was a vacuum leak in this or maybe there is a valve in these that's faulty this could cause the idle to go uneven. It maybe small enough not to be an issue under normal braking but under heavy use it may affect the idle. You'd be unlucky for this to go as I've never had a booster go but sounds like you're running out of ideas. Might be worth a look.