I've been trouble shooting this on my tracker as well and have got the problem solved for the most case. I had a loose vacuum line on the electrical valves on the left had side of the engine in the front looking from the front. I also replaced my head gasket and discovered the EGR system was completely stopped up in the intake manifold, exhaust manifold and the EGR valve. It has gotten better since then but still revs high at the beginning for about three seconds then comes back to normal and stays there. Hope this helps