getting hesitation when shifting at higher rpms

[DMmustangLX]

whats up guys finally got the notch back on the road this weekend and when i was getting on it a little i notice that when i went to shift at higher rpm that i get a hesitation. ill explain... after i shift gears mainly 1st. to 2nd. and let the clutch back out instead of chirping the tires theres a hesitation. the car has a speed density 5.0 which is getting converted to m.a.f i do have a vacuum leak under the upper plenum which is getting fixed this week. anybody ever run in to this issue any help will be appreciated

thanks,
drew

[White5.0]

the vac leak is probably what is causing it

[DMmustangLX]

yeah im going to change out the intake i think its the one vac. line that runs under the intake so im going to investigate and c what i find

[White5.0]

yeah if you are taking off your upper intake i would just replace all vac lines with brand new ones while you've got it apart.

i saw a pretty interesting thread on the corral before where a guy had a vacuum leak and couldnt find it unless the car was running. he had a pic of the vac line with the car off and a pic with the car running. when it was running, you could see the vacuum split open letting air in (vacuum probably pulled it open)... and when the car was off, the vac line looked perfectly fine.

so the point im tryin to make is that even if a line looks fine, it may have a very minor slit that you can't really see, so you should replace all of them

[DMmustangLX]

yeah im going to do all vac. lines around the intake and under i had the car running and sprayed throttle body cleaner on the vac lines and the rpms rise when i spray by the back of the intake i gotta do the trans. in my gt first and gotta do 31 spline rearend setup in my buddies stang so gonna do it after work sometime next week ill let u know what i find thanks for the info