It is not the caudalimetro

Greetings to all.
Vereis: I have a Seat Ibiza TDI of 98, has 145,000 km and has begun to cause me a problem that has me perplexed.
The problem consists of the following: I start the car in cold and I can be doing kms. Until the deposit is exhausted, that is: no problem has the car. However, when the car has already taken temperature, if I stop a few minutes, when I start again, the first thing I notice is that without touching the accelerator, the engine rises to approximately 1500 laps, to fall to a perfectly acceptable idle. Start the march and the few minutes begins to blink the symbol of the heaters, I am unable to pass it 120 km./h, and the minor costs, it falls apart.
I thought it would be the caudalimetro and I have changed it to a new one (€ 130) and the problem is still present.
I want to recidivate and highlight that the car does not present any problem as long as it does not stop and start the hot engine.
If I want the problem to disappear, I let the car get cooled again and make miles without problems or lack of power (until it stops again and start again being the car still hot)
What can happen to my car?
I await your suggestions. thank you

If the preheating indicator flashes with the engine running, indicates the preheating system failure.

Thank you for answering Jotorre, but you will see: the car starts perfectly, which induces me to think that it has no damaged bullshit; In addition, realize that these (the spark plugs) Once the car has started, they are "out of circulation", because their mission is very specific (healing the cylinders to enable combustion), so the truth is that the symptoms do not fit me, because I again indicate that the problem is presented only if I stop the car and start again, then it is when at a few minutes after the start, the march begins to start. Symbol of heater with the consequent loss of power. I don't understand.
Thanks again but I would appreciate more opinions.

Hear the circuit of the heater , although it is correct that these are inactive during the functioning of the cehiculo, there may be a problem which induces its operation on the march which would burn fuel before the normal explosion of the vehicle occurs, thus flowing into lost power ... greetings ...

Greetings Lufacana: There is no way. I have the bewildered car because, in the same way that the fault appeared, so she has removed alone. In any case, I have come to disconnect the cable that feeds the heaters and the flickering of the symbol of the heaters was still present in the El Dashboard box, but I already say ... the breakdown has disappeared without giving me options to be able to locate it. I noticed that I had already disappeared when after stopping the car once it had already been heated, I gave the start -up and the car "did not accelerate," I started the march and so far. We will see if it does not appear again. I said greetings