Volkswagen: 2003 Golf transmission, torque convertor, obd ii

Question
Lock-out clutch seized, transmission failed.  Rebuilt complete transmission 1 1/2 years ago, everything except case. Told some components were faulty from he start.  Then torque convertor seals failed, lost all fluid.  Engine fail light still on frequently, approx. 75% of time.  When light on, engine RPMs approx. 400 rpm higher than when light is out.  When light  goes out while driving, it feels like you released the brakes and the tach needle falls back.  The engine sound is noticeably different between light on and light off.  Help!

Answer
Dave,
 If I understand you correctly, you are getting a "Check Engine" light on and off frequently.  This may or may not be related to the previous transmission problems.  Rather than assume a connection between the two, you should get an OBD-II scan to pull the computer error codes.  This will tell you exactly what is triggering the light.  If you wish to DIY, I can explain that for you in a follow-up, or search the archives here.

- Rick