Have you adjusted the valve clearances in the last 30 or 40,000km? I did mine the other week after 30,000km, after rebuilding motor, including reconditioning the cylinder head. The idle revs shot up from 500 to 1000, and the car just flew out of the blocks leaving all others behind. It just wanted to go, go, go. I had to wind back all three fuel valves on the LPG system to get it back under control. Its just the L28. But what a difference when you re-set the valves to proper specs. A lot of people, including myself, tend to forget this engine tune up job.