Can't get past 4k in 4th

[k11_whore]

Some reason cant get past 4k in 4th but fine in 1st. 2nd and 3rd? That normal or something wrong ?

 

[gtsnissanb]

Knackard synchro?

 

[k11_whore]

I was thinking coil or spark problem or O2 sensor causin me to run rich mpg is down