i just did a b18b swap into my eg about a couple weeks ago and it has been driving and shifting fine until today i took it onto the parkway. well i was in 5th gear for about 10 miles then all of a sudden it pops out of gear. then i put it back into gear then after like 30 seconds it popps out again. when im doing 50 mph it doesnt pop out but when im at 58 and up it pops out after a couple seconds. what could be wrong any ideas or has anybody experienced this before.