Can anyone help.

I have replaced the fuel filter
I have replaced the spark plugs
I have replaced the wires
Cap and rotor were inspected
I have replaced the O2 censor
I have replaced the Temparature coolant censor

When the car is cold it runs fine, as soon as it hits 15-20 minutes on the road depending on the temperature outsided and moisture it starts to idle iratically, black smoke comes from the exhaust, for some reason the computer thinks the engine is cold and gives it more gas. When stepping on the gas it feels like it is going nowwhere, my mileage turns to crap. If I turn the car off for more then 5 minutes it runs fine again. It runs fine for a little while usually for another 10 - 15 minutes and then starts doing the same things over again.

I am a my wits end, this has been going on over 6 months and I am sick of hearing mechanics telling me that they don't know what the problem is, can anyone help?

Andre.

how's the air flow sensor? my friends car did the same exact thing because the afs was getting stuck open.

Thanks for the suggestion. I actually spoke to a VW Mechanic today, one of his suggestions was that it could be the mass air flow sensor.

I hope it is.

good luck! :smokin:

Andre so was it the air flow system?

Andre so was it the air flow system?

I have the exact same problem. Please let me know if the air flow system was the cause.
Thank you,

Another common problem is the idle stabilizer valve. It's the cylindrical thing connected by hoses to the throttle body and intake. It gets stuck. Remove it and clean it with carborator cleaner. make sure the metal valve (piston looking thing) can move up and down freely.