Hope maybe you can help my 350 ramjet has only about 20 hours on it - it runs fine when cold but as soon it gets to 160 degrees it starts to have a miss and hesitant s at about 1500 rpm and to about 3500 rpm, also the rev eliminator starts at about 4000 rpm hope maybe you might have any ideas.
That sounds like it is going into closed loop when the miss starts. Does it have an oxygen sensor? Is there an exhaust leak before the sensor? If there is the O2 picks up the leak & adjusts the fuel trim incorrectly.