I'm having a problem along these lines that showed up on my second test run. Since pulling the engine out of my A-4 and installing in the L-39 the idle stability jumps around. It's showing between 54000 and 58000. It does not want to settle down to a very reliable 55K as when I had it in the A-4. There are two main differences, in the A-4 there were no servos near the engine and the fuel tanks and pump were located very close to the turbine. In the L-39 the elevator servos are on either side of engine center and the fuel pump is all the way up at the nosewheel firewall. I'm sure the long run of small diameter full line from pump to turbine is causing a slow response in the overall control loop. Is there something I can change to test this out. The idea of coming in to land with the power above idle , even a little bit is disconcerting. I want to maiden Saturday, so what do you guys think? Doug