alizzz, hello agen. I need your expert advise. I have non turbo 660cc, it originally had a 6.57 diff ratio, luckily, I found a 3.88 that directly fits to its carrier without any alterations. I am satisfied with its speed from 1st to 4th gear, but on the 5th gear no matter how much I push the pedal, it doesn't seem to react anymore. The estimated speed when in 5th gear is around 70km/h at 2000rpm, estimated speed since the speedometer only reads 40km/h because of the diff change.
What do you think is the problem, is it the engine or a tune-up issues. Im thinking that its the fuel filter, maybe it doesn't get enough fuel. Pls enlighten me on this.
Note: I didn't change the engine.