My 1999 IH 4900 dt466e begins to sputter, vibrate, and lose alot of power under load. The sputtering/vibrating starts anytime acceleration or load demand is put on the engine. I did replace the fuel filter primer assembly when I noticed fuel leaking from it when you pumped it, fuel coming out equels air getting in, so replaced it and got alot of missing power back, but I still get the flutter, vibration, and power loss under load. When mine starts fluttering, you can hear what sounds like an exhaust leak. I checked the exhaust, and found no large leaks, I did find a small leak around the band that clamps the exhaust pipe to the turbo, but it is very small, does anyone thing this could be causing the fluttering and power loss under load? Reduced pressure of something? Mine seems to run great cold and the fluttering response comes on as the engine reaches operating temp. When the fluttering starts you can slowly back off on the foot feet and there comes a point when the fluttering stops, engine smooths out, and you can notice a sudden increase in power, if the engine pulls down more or you give it some throttle, the sputtering starts again. It eventually will sputter up some RPM's, but very slow and labored. I repaced the cam sensor about a year ago. This is driving me crazy. Any suggestions greatly appreciated. Thanks.