Sluggish in low gears and uphill - could it be the AMM?

I've just bought a 1999 1.9 TDI.

My problem is that it is quite sluggish when accelerating hard in low gears (1st-3rd) and also going up hill in general it struggles to keep the speed up - if I'm on the motorway doing 80mph and I hit a hill it rapidly slows down to 60mph but then doesn't generally get any slower.

Another curious thing happened on the motorway on the flat - I hadn't had the car over 80mph and wasn't sure if it would go....I pushed it and it slowly got to 85mph, at which point it took off and accelerated to 100mph in a few seconds! Is this normal? I used to have a 1998 mk4 with the same engine and have never experienced this.

Back to the 'sluggish' problem, I took it to local independent VW garage who I had asked to look over it. They didn't spend much time on it but did hook it up to VAG COM. They said they couldn't work out why it was sluggish but on a separate note advised it needed a new AMM...having read a few threads I'm beginning to think the two could be related?

Any advice appreciated.
Thanks.

My method is “No codes, no power, new AMM”. They are easy to fit but only buy one from a VW dealer or TPS, do not be tempted by lower prices for so called “genuine” AMM’s anywhere else.

Sounds like the AMM. When mine went the car behaved normally at very light throttle but there was a mid accelerator pedal position beyond which it was as though a giant hand was holding the car back. Changed it myself and it was back to normal.

Follow Crasher's advice - if you're getting one go to a main dealer with your car's reg. number and they'll look up the correct part. It's pretty easy to fit but beware, if the plastic parts on the air filter box are warm it's easy for them to distort allowing captive nuts to spin in their sockets which then become a bugger to undo. If I do one again I'll remove the hose from the AMM and then take out the air filter housing complete with AMM, let it cool and change the AMM.

Thanks guys, probably saved me a lot of time and money. I was planning on just taking it to the main dealership to have the work done as well as get the part as I'm not 100% trusting of my local VW expert now.