1999 volkswagon jetta engine revs up high when i reach about 40 miles per hour

do you mean revs up like it's in neutral? or like a downshift?

like in neutral.

whats the dfference i meant to ask if you dont mind.

a downshift makes rpms jump but also slow car down with no feeling of power loss. did you take it to dealer for diagnosis? are any engine warning lights on?

yes its more like the downshift your asking about it does lose power or try and quit.Dealer cant find out what the problem is.

still not sure what is exact symptom you are trying to describe. are you saying it fails to shift into highest gear or it just takes longer than it should?

It try's to take off with me while I'm driving the Roma go way up.

so rpms rev up with NO increase in speed? or it downshifts and revs till it cant go any faster? i mean does it reach a high gear and go fine until this just happens fro no reason on your part?

It is running faster than it should do these jettas have an idle control motor?

It start doing the revving up about 40 miles per hour and when you slow Down its still running too fast.

It's going into gear don't think it's a Transmission problem.

did you get charged by dealer for not finding problem? they must be idiots!

No they just charged for the crankshaft position sensor that helped to car quitting and now it has this problem.I just wondered if it had to do with another sensor such a Idle control motor but don't know if that's what it's called on the Jetta.

did this problem start right after the other work was done?

Yes it did fix that problem.

I was wondering if it could be the Throttle Position sensor what do you think?

you need to in very good detail explain problem again. start with putting key in ignition and then start car and then....

Ok I'll get back to you tomorrow and go from there.

you should have an electronic throttle on that model and possibly the throttle plate is dirty sticking and not relaxing when you let off pedal so when you accelerate it just keeps going after you let back to cruise.

Ok thanks I'll try a few things and let you know.

it's a tricky issue to clean it if its sticky! dont attempt without instructions!

Ok thank you.

Having a repair shop hook up the specialized VW VAG scanner and capture live data while the problem is occurring might help greatly. Maybe the fuel pressure regulator is malfunctioning and delivering too much pressure to the injectors.