Toyota Tercel 97 Automatic 5e Motor

I have problems with a Toyota Tercel Automatic 97 starts without problems but when it comes to exit it has no strength, but if I take some speed there it is another story it normally makes all its changes etc but if I stop again it is the same is the same. The problem started a week ago and every day this worse was found fuel filter, it was reviewed that the catalyst was not clogged I wanted to verify if it was a problem that perhaps did not towards the operation of Kitdown I made the changes manually but that is not the failure and when it is working well after taking speed if I make the changes manually to buy the box it works perfectly

I could help you but I need more information, l consumption of fuel, use GNV and if you can tell me something else we fix it ok