car runs very sluggish after it heats up

[philgn8]

I have a 87 GN with very few mods.(8 inch K&N, Kenne Bell chip) The car runs great when I first start driving it but after about 15 minutes of driving time it starts to run terrible. It dosen't shift right, it is a very jerky ride. The turbo dosen't seem to operate the right way or at the right time either. I have noticed that my rpm's seem to be higher at all times. I don't know if that has something to do with the problem. Can anyone help?

[Keller]

Do you have acess to a scan tool?

The Kenne-Bell chip is very outdated. There are many more modern options. This is not likely the (entire) cause of your problems, however.

[philgn8]

I don't have a scan tool. What one would you recomend and where can I buy it?