I noticed a slight loss of power or flat spot way up on the rpm's of 4th gear only??? I dosent happen in any other gear and it only happens when I crank up the boost. The fuel mixture seems ok when i checked my halmeter. Any ideas bf I start trouble shooting?

specs are- b18c, 62-1/t3, drag 2 IM, greddy profec (fuzzy logic one),12psi base;14psi hi boost. Greddy bov(the old blue one cant remember the name) haltech e6k, racegate wg.

 

maybe a clog fuel filter or fuel pump getting weak