Hello I'm new to this an I have a problem that no one seems to be able to figure out figured I'd give it a shot... I have a 96 gt an car runs good but when your driving it an you get to 4000 rpm it starts cutting out an spark rattleing. The car want pull any harder but the tach keeps climbing an I'm at a loss my brain is fried ive read every thing I can find about it an nothing found... Has new plugs an wires coil packs an maf sensor fuel pressure it's good at idle an wot...I logged some data on it an at 4500 rpm it's saying 54% load.maf is reading 142.8 an spark advance is at 17 and imrc is at 2.26 any help would be must appreciated