Having trouble with my 90 Loyale. 1.8 not a turbo. Runs fine for a while then, as I accelerate to 3000 rpm to shift, the rpm drops and I have to slow down for the engine to catch up with itself. Occasionally, in neutral on the 5spd, I can depress the accelerator and the engine will rev to 3000 and drop repeatedly at precise intervals. I just bought this thing two days ago. I changed the fuel filter immediately, filled the tank with premium and a bottle of Gumout water treatment. Still does it. Anyone?