Galant 2.0 GLS TDI - Random loss of power when accelerating

[Xoliveira]

Hi 
1st of all thanks for the time you guys are spending on my topic.

I'm new at this forum
I'm having a trouble with my Galant 4D68  engine aceleration. It randomly exhitate on aceleration.
Sometimes going down a hill the Service Light switch on, and when it happens if I press the acelerator pedal it reacts as almost no pressing it... and if going up a hill it only runs at 1st gear at 2000 - 2500 rpm (more or less) as no power at all... the car just runs as in safe mode...the idle is perfect, no smoke, no noise, temperature looks ok; just no power at all...
I was wondering may should be the crankshaft position sensor... but already check with multimeter and it looks ok...(anyway it's a random issue)
If I restart the engine the power is back again and everything looks good again and the service light switch off.
other information is that I noticed that when weather is hot it happens worse and much frequently...

any information or tips is really apretiate.

thanks guys
Xavier