Random Car Judder/Stagger/Misfire-like symptoms I'M DESPERATE

[Dan_Nelson]

This is probably impossible to diagnose from my descriptions but have a look and see if any of you whizzes can point me in the right direction.

My 2007 Golf 1.9 TDI Match (Diesel) conked out on the way to work the other week. Engine Management Light came on along with the 'Drive to Workshop' message. It was virtually undriveable but I managed to get it to a garage.

At the garage, the mechanic ran a diagnostic and recommended a new crankshaft position sensor (engine speed sensor). Owing to the position of the sensor, he suggested a clutch and flywheel change while down there. I accepted..to the tune of £850.

Anyway, got the car back a few days later and something felt off. It took a few days to manifest but the car was intermittently staggering, felt like a misfire but it couldn't be predicted. The car felt like a loss of power for 1/2 second and then back to normal I took it back to the garage, the mechanic changed the Injector Loom. No effect, the stagger kept happening but I was told to keep driving it until it manifested itself more obviously.

The car then started to conk out on me at low speeds (coming off the motorway, round the town), Engine warning light on and then off, the stagger was worse, a very quick succession of power loss and then a brief power surge (probably lasting just over a second). I managed to get it back to the same garage and, suspecting the replacement sensor was faulty, asked him to replace it on warranty. He did. The car showed no record of engine management light and warning when a diagnostic was run.

Anway, I've just picked the car up again and less than two miles away from the garage, the Judder/Stagger is back. I'm already down a grand (including the injector loom replacement) and I have no idea where to go next.

I find it really odd that the car has had a Crankshaft Position Sensor replacement and then has developed a new fault like this. I'm at my wits end. Could multiple things have failed when the CPS went?

I've considered fuel injectors and fuel pumps but I'm really not sure. One other thing worth noting is that the fuel gauge has a fault. When the car has over half a tank of fuel in it, the gauge will sometimes drop to zero and not show a reading. When the car is restarted, the gauge reads fine. Not sure if this is symptomatic of a larger problem. I've read that faulty glow plugs can cause misfires but what about the engine shut down I've experienced?

I hope someone can help me.

[tditaff]

What diagnostic equipment was used for the scan?
VCDS (or equivalent) needs to be used to obtain correct information to base fault finding efforts on.

[micheal balbrig]

Yes, a scan with a good garage would be first starting point.
If it was mine I would probably check out the engine timing for peace of mind and to eliminate it as a problem.
Then the chase could begin for the many possibilities.
Is it possible that some wrong fuel may have been put in tank?
It is unlikely that glow plugs would cause your problem.
A faulty anti shudder valve (if fitted) might be a suspect.