Yes there is a Fuel Pump relay.
On an '88 it should be on the passenger side inner fender just off center towards the cab.
It will have a Green Base/Plug.
There will be another relay near it with Brown base/plug, that is the EEC relay it powers computer, spark and injectors.
Intermittent fuel pump is often that relay, and it is worth replacing, it is just a standard automotive relay, nothing special or expensive.
You can manually operate the fuel pump relay to test if that is the problem.
Look at the second drawing on this page:
http://www.therangerstation.com/tech_library/OBD_I.shtml
That is a drawing of the Computer test port found near the firewall on drivers side, but have found it on passenger side as well.
Find that connector.
The slot labelled Fuel Pump in that drawing is the Ground for the fuel pump relay.
You can hook a jumper wire from that slot to a Ground.
If key is ON then relay should click closed and fuel pump should start and stay running if that jumper is in place.
In the relay plug/socket there should be a #30 and #87, if you put a jumper across these 2 slots the fuel pump should come on, key on or off won't matter, #30 is 12v from battery, and #87 is hot wire to fuel pump.
Picture of relay pins/slots here:
http://dodgeram.org/tech/gas/Trouble/Fault-42.htm
Ford, dodge, chevy, ect..... doesn't matter they all use the same standard relays
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