Volkswagen Polo Classic 98 ignition problem

First of all, the battery, if it is okay, give it with the start that is the most common failure in these cars

Thank you very much to everyone, in principle with a cleaning of the terminals of the battery the problem was solved. A mechanic that reviewed it told me that the "I don't know what" the Flip, I don't remember.
Anyway I had to sell that excellent car (which had absolutely no other problem and had a beautiful walk) to build my house. But in the future I will repeat the model.
Thanks again to everyone.

I had a problem similar to yours and solve it by changing the injection relay, I was unused and did not fed well to the ECU.- Luck.- Miguel.-