Hey everyone. I got a Toyota 7FGCU25 with a 4Y LPG engine with about 25500 hrs on it. The problem I have is under constant high RPM load the engine will start to shudder and backfire, let go of the throttle and after about 45 second it clears up. If it does shut down and u go to start it, it sounds like no compression. However if you hold down the ignition it will eventually start and run great until u give it a constant high RPM run. The tune up has been completely done. The oil is new and even a Lucus Oil treatment is in. (Customers choice, machine run almost 24 hrs a day). Does anyone have any ideas. I have tried to check compression but by the time I get the gauge on its ok. Same with trying to inspect the lifters. I am ready to blow this thing up and tell them to buy a new unit.