Jaguar S Type V6 intermittant idle

[jokeruk63]

Hi all,
I've purchased an year 2000 Jaguar S Type V6 yesterday as an interim run-around as my daily drive got totalled last week so a speedy cheap purchase was required.

So, £500 later I have an unmarked S-Type with a genuine 66K miles on it and a full service history however....It does have a problem, and I was aware of this before purchase.

It has a rough idle when it warms up that rises an falls almost to the point of stalling. Also and I think the two are linked as soon as you drive up a hill at a fixed speed there is a continuous hesitation if you don't move the throttle. If you increase the throttle on the hill it is smooth and pulls fine so I don't believe it is anything serious (famous last words, you don't get something for nothing etc)

Anyway, does anyone have any ideas, had the issue themselves or got any pointers?

As usual all advice gratefully received

Steve

[melhookv12]

Airleaks, or failing coils.
There's 2 rubber hoses at the back of the manifold, as u look at it centre below wipers.
You need to remove the manifold to get to them. So when it's off I'd do the coil packs under there and the plugs.

Get some wd40 and spray it around the back of the engine doo if idle speed changes. If it does then it's an air leak.
I'm guessing no check engine lights on?

[jokeruk63]

Hi,
Thanks for your reply and advice.

No lights and no codes.

I've placed an order for 3 coil packs, 12 manifold gaskets and a rubber elbow hose for the vacuum pipe under the manifold.

Hopefully it will come apart easily enough - I will let you know.

Steve

[melhookv12]

There's 2 rubber hoses, one is easy to get to the other I think you have to remove the metal pcv.

[melhookv12]

The top pic is easy to change in situ, might cure ur problems, it connects to the second pic, the elbow hose fails.

[melhookv12]

You dont need 12 gaskets, think they are 1 piece per side, so you onlu need 2. ie upper gaskets

[jokeruk63]

Ah - more useful advice - The pictures look really helpful.
I think I've ordered the lower elbow pipe - The upper seems OK

I called Jaguar and they suggested there were 6 upper and 6 lower gaskets if I take the manifold off - hopefully I can return them if they are not needed, but living in the wilds of Wiltshire I can't just nip out to get stuff.

Thanks for the help folks

Steve

[Cool Mart]

No advice for your problem but a word of warning .... I also bought my 2005 V6 S-type as a 'stop gap' after my Golf R, as I just couldn't decide what to get next.

15 months on and I've still got it !

It starts on the button every morning, never gives me any grief, has cost me about £200 in odds and sods, I don't worry about the kids eating in it, it doesn't feel right to rag it, it depreciates at about £30 a month and I get to waft around in comfort.

Every time I get close to deciding on something nicer/quicker I just think how easy it's been to live with over the last 15 months

I think I'm getting old ...

[jokeruk63]

Ha! Well assuming my guess on the seriousness of the problem isn't completely wrong then keeping it longer is a distinct risk! Given the low mileage it was almost too good to be true - but I suppose that real value of the car when working is really low as the S-Type does not seem to be well liked and values are low at the best of times.

I wanted a cheap car as I'm going through a divorce and expensive assets are to be avoided at all costs!

I've only driven it the once 45 miles home from Bristol and even with the irritating idle issue it seemed very nice, everything worked and it was very comfortable.

[jokeruk63]

Hi all,
Removed inlet manifold and replaced collapsed and ruptured elbow pipe - also changed plugs and coil packs.

Much happiness as I now have a nice smooth idle.

Many thanks for the advice


Steve

Just thought I'd add, the instructions I used are here http://www.jaghelp.com/2012/03/intake-manifold-in-...

But there are two areas where I went off-piste (maybe because mine car is MY2000 , one was in the disconnection of the fuel line - I didn't have the required disconnection tool and discovered that the plenum chamber can be gently wiggled aside allowing access to the pipe below and leaving enough space to clean the ports and gasket faces.
The second difference is in the article much is made of a high likelihood of breaking the nipple on the upper radiator hose. I'm not sure I went near this during my disconnections again maybe a difference due to model years - but other than that the job was done in about 2.5 hours.

Edited by jokeruk63 on Monday 18th December 12:12

[jokeruk63]

OK I may have been slightly premature....
The previous problem has definitely gone away as the idle was massively erratic and now it is 100% better.
However, I've had it on idle for about 30 mins and there is a very slight unevenness with occasional dips up and down.
Does this suggest there maybe another vacuum pipe requiring my attention - I thought I'd looked hard at everything and sprayed quickstart around but maybe not.

Once again all suggestions and ideas gratefully received - I'm wondering about the top elbow although it looked OK

Steve

[melhookv12]

Check the swirl flap o rings on back of manifold, I've had the o rings leak air before.
If you have the right equipment you can check short term fuel trims which will tell you if it's an air leak.