Hesitation, is this fuel related?

Okay here I am again. Another problem with my 88 toy 4x4 with the 22re. Lately, when the rpms are kinda high, like before a 2-3 shift and a 3-4 shift, or just when the revs are up there. The check engine light blips on and off, on and off, on and off, and the truck kinda like hiccups. The higher I keep the rev going, like If I'm in 5th gear already and I lay on more gas it won't want to go any faster. It just keeps on like "hiccuping". Im wondering if this is more a problem with the fuel system, or would this have more to do with the transmission?, or I have a feeling its the fan belt slipping? because this hiccuping is similar to how it felt before the fan belt broke? not sure though cause the fan belt I replaced it with is not broken....well im not too sure if my description is helpful, but any help will be appreciated. Thanx

Have you checked the fuel filter yet? Based on your description, sounds like you're losing fuel pressure or you have an ignition - based misfire.