Just wanted to pass my latest success along. I purchased a 1990 Ford Festiva with 225,000 miles on it.  This vehicle is powered by a Mazda B3 engine which is a downsized version of the Mazda B6 engine powering the Mazda 323. When I purchased the car, it had one collapsed lifter and the rest of the lifters were quite noisy.  The engine was very loud and lacking in power.  A group of GTech HP runs were made and they averaged out to 38 HP at the wheels.  Fuel economy before the Auto-RX run was 29.7 MPG city.  This car is used for a very grueling Houston commute. The Auto-RX was put into the Castrol GTX 20W50 oil which had 2000 miles on it.   Over the next 75 miles the engine began to smooth out and the noisy lifter began to quiet down.  At about 75 miles the collapsed lifer begun working again.  Over the next 1400 miles, when the oil was changed, the engine became smoother and stronger, going from the baseline of 38WHP to 55WHP, which is what the vehicle was rated at when new.  Fuel economy climbed to an average of 33.5 mpg city.  The engine is exceptionally quiet now and people comment on how quiet it is.  People who have driven the car comment on how well it runs and find it hard to believe that it has over 226,000 miles on it.

Wayne Bengston
Houston TX