This is what he wrote about the motor on that forum
I assume your looking at nothing older than early 90's? I have a old 84 s-15 with a 2.2 diesel, it's ugly, gutless and noisier than hell but amazing fuel mialage (est 45-50+mpg and thats concervitive).
Overall I've heared conflicting stories from many people about these engines (gas ones anyway). pretty much comes down to how well maintained it is and how much power you want to sacrifice for better gas mialage. unfortunately you can't get it both ways.
I can probably get a contact number if you want to find out more