VW Polo 1998 Model runs fine for about 5 km

The first thing would be to get a readout of trouble codes from the car's ECU. That will give you pointers on what needs fixing.

In the USA Autozone will do this for you, or any competent mechanic elsewhere.
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MAYB CAR NEED ALINEMENT

Hi i have a vw polo 2009 model petrol I was driving at 25mph the car lost power right down to 0mph then the engine cut out on me and now it will not start can any one give me a clue what it could be i have changed the spark plugs and changed the spark plug leads and i have check the fuel pump and still wont start

start going through all of the body and engine grounds. look for any that are corroded or loose. Had a similar issue on a domestic vehicle. It had been at the body shop post my wife wrecking the car. The body shop left half the grounds off or loose. The thing was going nuts. Spent two days looking in, under, and around the enngine bay and found a body ground off on the lower firewall. The car went right back to normal as soon as I re-attached that one body ground.

Most probably that can happened because of battery fault.( Weak battery) if not need to check with vehicle scanner for electronic side.

Has the car been serviced recently?
If not I would suggest getting it done.Not sure if you have diesel or petrol, but oil can thicken causing more load on the motor and airfilters get blocked and can cause a rich fuel mixture.

If petrol you can take out the plugs to check if they are a light brown colour, if very dark or black you need to check and adjust carb/injection settings/filter.Need to know what engine it is really.

Red this article:

Eventhough the level is right, the fluid might need replacing (every 3~5 years and 50.000-100.000 miles).

You can read how to recognize bad/old fluid here: http://www.hondaclub.com/forum/articles/1492-power-steering-fluid-lifeline-your-steering-system.html

Hi, I have a 2001 polo 1.4 mpi it lackes power when you hit a hill it just dies, It has had new cat, fuel filter, fuel pump and throttle body, but is still the same it just dose not want to give me full rev's?

you have an loose connection on an electrial circuit,check your battery connections,most likly alterator wires,.adrian.;;;;l

Bought a very reputable diy service manual for the vehicle, and that plus a bit of thought and nous gave me the cure: no intrinsic problem other than loose relay connections. Went round with the wiring diagrams as guide checking all electrical connections in tight and relays fuses etc all good. Switched on and no problem any more.

By the way, vehicle is 1992 VW Polo - not Fox (which in UK is a variant of the Polo)