My yj is stick by the way, the thing is that i feel like the engine is bogging, i cant use the 5th gear or go over 60mph, gas milage is poor and it feels heavy as hell
If the engine's bogging down then I think it's more because you're not reving the engine so it's in the powerband. Poor gas mileage is probably because your speedometer is off as well. The PCM gets thrown off because the speedometer is off. Gas mileage shouldn't change (with a gear change) over stock as you should be turning the same RPM's as you would have stock. If you're lugging the engine, by not reving high enough and also because the speedometer is incorrect, it will effect mileage and performance.