Maybe your engine is dirty? Try the
Engine Scrub [ESCRB1] - $9.99 : KaleCoAuto, Hard to find automotive items! to clean your dirty engine!
Also, your engine is probably too hot...it's a simple matter of physics that energy is lost through heat! The
Radiator Insulator - $199.95 : KaleCoAuto, Hard to find automotive items! should take care of that.
And if all else fails, try this
Flux Capacitor [FLUX62] - $175,000.00 : KaleCoAuto, Hard to find automotive items!
Good Luck!