VW Golf - Loosing Power/Gear Change?

[VillaGolf]

Hey guys,

I've had some issues with my Golf (Mk 4 2000 2.0L Auto) for a while and haven’t been able to find a fix.

Symptoms: Car gets to around 60km/h and starts to lose power. The revs increase to 4.5k with little to no speed increase. I change the car back into 3rd gear manually and then once at around 65km/h back into 4th and its fine.
This only happens on occasions (I could drive for an hour and it will happen maybe 2 times or 10 times) and it happens at the same exact point on certain roads.
It can also occur when the car is already in 4th gear. For example, when I’m on a freeway travelling at 100mk/h with ~3k revs it starts to lose power. Maintaining my speed doesn’t push the revs too much higher but trying to increase the speed even slightly sends the revs towards 5k.
Other: The car squeals a very high pitch sound from the left front side of the car once the car is going > 30km/h. This may be completely unrelated.
My Catalytic Converter also got stolen and I haven’t gotten around to replacing it (was advised not to). Could this be a cause at all?

I’ve had two mechanics look at the car and they have failed to provide any solution.
Volkswerke in Greensborough have drained the transmission fluid and found no signs of any problems (they were looking for metallic parts as a sign of damage).
As you can imagine this is becoming an expensive trial and error game for me and I’m looking for a more definitive solution.

I had a friend who believes the timing belt is loose and needs tightening (claims a similar thing has happened to him) however no mechanic I speak to considers this to be a possible solution.

While I have managed to handle this issue (and hopefully haven’t caused any additional damage) I’m now looking to sell the car and would like to fix this problem and not handball this to some unsuspecting victim.

Thanks fellas

[Manaz]

Someone stole your catalytic converter? Doubt this would cause the issue.

Timing belts don't get "loose and needs tightening" - I hope your friend is a better friend than he is a mechanic . Timing belts wear out and need replacing (and preferably before they break and then your pistons and valves need replacing). And if they have loosened due to wear, they'd probably slip a tooth or two, and you'd have consistent issues

My intial gut reaction was transmission related - it sounds like the auto gearbox is starting to play up. Burned fluid or metallic bits in it would be a good sign (but may not necessarily be there if it's something loose or a blocked valve or something - I'm not sure if the VW autos use the traditional "bands" and solenoids of older-style automatic transmissions.

I hope you didn't pay too much for a simple transmission drain and refill...

A sudden jump in revs though could be the gearbox changing down a gear, which it may do because it's losing power. Seems unlikely the car would do this in exactly the same spot on the road each time though.

Has the ECU been scanned for error codes that may help indicate the issue?

[JustCruisn]

If it were a manual I would say your clutch is failing. What is the auto equivalent ?

And what it the story with your cat ? They don't get stolen FFS. That would require removing the exhaust, cutting out the cat then welding in new section and putting it all back under the car. You'd need a few hours to pull this off.
What make you think its been stolen ?

How long have you owned this car and what it is service history like ?

[VillaGolf]

Haha yes my friend that mentioned the timing belt is an Occupational Theropist, probably best he sticks to that!

I should have added, at those points in the road where this occurs there is usual a slight hill involved, but not always.

I think its transmission related however I believe the mechanic ran the tests with no faults. And the fluid drain was around $400 from memory...
I tested it on the way home today, when it happens at 60km/h it has less power than 1st gear but doesnt seem to be neutral as there is some power.

I've had the car for about 2.5 years and this first started happening over 12 months ago. It hasnt got any worse in that time.

And with the Cat being stolen, my mechanic told me that and said it happens. This was in 2010, apparently people were stealing them and selling the scrap metal for a few $100.
I just goggled to make sure I hadnt been sold up the river There are a fair few articles there.

[Manaz]

If it were a manual I would say your clutch is failing. What is the auto equivalent ?

Torque Converter (or lock-up torque converter if the Mk4 auto has that function). Fluid which has "gone off" could cause something similar if the transmission is getting to a particular temperature and it's going to **** (basically, the faster the transmission spins in an auto, the "more solid" the fluid should get in the small spaces in the torque converter (this is how the transmission allows more "slip" at low revs - the fluid is more "fluid" when the transmission is spinning slower (sorry, can't think of the word to describe the fluidity of a fluid).

And what it the story with your cat ? They don't get stolen FFS. That would require removing the exhaust, cutting out the cat then welding in new section and putting it all back under the car. You'd need a few hours to pull this off.
What make you think its been stolen ?

That was my thought too.

[kapowww]

And with the Cat being stolen, my mechanic told me that and said it happens. This was in 2010, apparently people were stealing them and selling the scrap metal for a few $100.
I just goggled to make sure I hadnt been sold up the river There are a fair few articles there.

My mate's in the "precious metals" industry and they go around buying old cats and selling them to China. It's a great business and they get lots for cats from Euro cars.