A little throttle to fifty percent throttle is not any issue and would not give vibrations btw. I am accomplishing 28 mpg max now with simple driving and often reving to max 7k, but only in some cases! Remanufactured Engines are absolutely disassembled; heads, blocks, cranks & cams are machined https://edgarpqyby.bloginder.com/29706396/jdm-toyota-4a-ge-for-dummies