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Matt
Matt, Mechanical Engineer
Category: Audi
Satisfied Customers: 21600
Experience:  BEng hons Mech engineering, in auto industry 22 years
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A4 2.0 TFSI Quatro 2006 steering wheel and seats vibrating

Customer Question

A4 2.0 TFSI Quatro 2006 steering wheel and seats vibrating when on idle increased noise form the exhaust when driving does vary and is considerably less today yesterday it was really noisy like exhaust was leaking. took it to the garage yesterday afternoon and they have looked it today - nothing came on diagnostic and they could not find anything wrong with it.
Few months back it had felt like misfire now and than but did not register anything on diagnostic when they checked it today.
Last few days I have noticed for a car to make a single clink noise when on full lock when coming out of my drive pass the ramp but it is fine while driving.
There is also an ongoing problem that is been going on for months and months sometimes when I put the clutch down the car jerks a bit. Garage has been looking into this problem had changed hips of parts and has cleared all the list of faults (including idling being to high) that were appearing when running the diagnostic but this one could not figure out and it is still ongoing.
I would really appreciate your help.
Submitted: 2 years ago.
Category: Audi
Expert:  Shantal-Mod replied 2 years ago.
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Expert:  Matt replied 2 years ago.
Hello

I'd 1st check for worn mountings - check the tightness of the engine and gearbox mounts and their condition - this is best done by using a jack to take the weight of the engine off the mounts and seeing if any cracks or splits open up in the rubber.Also check the tightness of the mounts bolts

if this is OK then check for a broken or defective driveshaft vibration damper - some models feature a rubber mass about halfway along

the driveshaft - this functions as a vibration damper so 'tuning out' vibration - the rubber needs to be not cracked and the damper firmly fixed to the shaft and running true - anything other than this and the entire shaft will have to be replaced as they are bonded in place

Customer: replied 2 years ago.
Hi thank you for your answer. Strange as it might sound but yesterday afternoon the car started to drive much better. Even though the vibration of the seat is still there while in idle but this has decreased rather a lot and with it also the noise from exhaust has gone and the car is driving rather smooth but the jerk when I put the clutch down is still happening now and than.
And this issue with clutch that I have for over a year now is a very strange and the thing is that it can happen as soon as I start driving and sometimes it could take 30 minutes into driving without any jerk and that it starts and it changes from being random and les frequent to as frequent as every third time I put the clutch down but never every time when the clutch is down.
It can also very in intensity sometimes I can really feel it badly and sometimes it is hardly noticeable so it might no be the mounts and the garage did say it has looked into this and are running out of options.
Three times in the last year I felt something like a misfire and than the car drives fine after this when checked on diagnostic there was no record of this so I doubt that it is a fuel injector. Any other thoughts?
Expert:  Matt replied 2 years ago.
Hello

Ok

one thing to check is what fuel you're running the car on?

as I know the TFSI engine is sensitive to this

if you use supermarket blends then this tends to be the cheaper stuff and can also suffer from contamination

from my own findings its worth paying the extra for BP or Shell as typically you'll get another 6-8% fuel saving which outweighs the cost over supermarket fuel.

this would also account for misfires and rough running that comes and goes and it would also be worth replacing the fuel filter for the same reason
Customer: replied 2 years ago.
Hi Matt I totally agree with you re cheep fuel that is why I always use 95 oct rate Esso fuel. I have tried BP and shell 5 years ago when I bought this car but it run the best on Esso fuel. I found that every make prefers certain fuel it shows in car's performance and fuel savings. In the past I have used fuel cleaning chemical ( when I had problems with the car 2 years ago and it turned out to be a fuel injector that got replaced and the car run perfectly for a year and than this have started. I will be replacing the fuel filter in May when the service is due.
Any other suggestions? My garage wants to try fitting new coil and rotating it till improvement shows. It seams that this car is very complicated as every issue I had with it was so difficult to detect and now without any info from on board computer it is getting even harder to find it. Any more thought?
I kind of thinking if it it a fuel injector why isn't it showing on diagnostic and why would it jerk when I put the clutch down and why is it so random it really got me and my garage in wonder.
Anything else you think what might be the cause of it?
Expert:  Matt replied 2 years ago.
Hello

intermittent faults are always the hardest to solve , and trying a new coil isn't a bad idea but as you say it may take a while to try all cylinders

This could be a wiring issue as things tend to expand when hot and its possible a poor or partial electrical connection is being pushed apart on one of the major sensors so check the connection plug and wiring to the following;

Airflow meter

Crank position sensor

Cam position sensor

O2 sensor

Throttle position sensor

Matt, Mechanical Engineer
Category: Audi
Satisfied Customers: 21600
Experience: BEng hons Mech engineering, in auto industry 22 years
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Customer: replied 2 years ago.

Hi Matt I have rated you and have also made a tip payment but I am not sure if this have reached you.

After a week of car working lovely apart form little jerk when clutch is down (every now and than not all the time) Yesterday the car started to vibrate really badly while in neutral just idling and making a lot of noise while accelerating and in gear driving.

I have took it to the garage today and they could not see anything on the diagnostic machine but we have discovered something quite strange while not in the gear and idling when we have switched the air-conditioning off it has started to make more noise and had more shaking than ever and that has increased when adding gas (while still being in neutral) as soon as we have switched the air-conditioning on the vibration has significantly been reduced although still there and slightly more vibration while adding gas being in the neutral.

Also when I turn on the car after 5 -6 hours not being driven the revs go up to 1300 and stay there for quite some time as soon as I put it in the gear revs work O.K although (it might be my imagination the rev needle does not go down as quickly as it should).

Now what was the usual for this car is that the revs always went up a bit (1100 - 1150) when I turn on the car but do go down rather soon after 20 - 30 seconds

Any thoughts on this two new discoveries.

Expert:  Matt replied 2 years ago.
Hello

thanks for the positive rating and the tip

I'd say its well worth checking for an airleak after the airflow meter, any air dragged in here isn't 'seen' by the ECU and so not compensated for and can lean the engine out and can also allow the engine to rev up when not desired causing rough running.

As its a mechanical fault it tends not to turn on the fault light and you can sometimes hear a 'hissing' noise with the engine running.

Check the hose clips for tightness and inspect the trunking for any cracks or splits and also all the vacuum system, the small bore pipes and fittings for cracks and missing parts.

The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane around each joint in turn. If the engine rev's up you've found your leak.

Now you might think that spraying lighter gas around a hot engine isn’t wise, however the flash /ignition point of gas is about 400°C so you need a naked flame or spark to set it off and I’ve used this method for many years without incident.

Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.

It’s also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will all result in insufficient fuel being delivered to the engine