I would check the junk yards, those type of fuses last forever and from 85 and all the between years should have the same setup as your 88 and even up to the 1995 22r motors. As long as they're fuel injected which shouldn't be an issue since fuel injection was introduced to alot of the trucks in 85. Come to think of it my carbed 84 has a couple of fuses that size.
If you want to get robbed again then ask the dealerships and see if they have em but that would be last resort.
Hope this helps
