you know we really can't tell what may have happened from here.
test the pump for flow while starting.
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i can offer you a full "factory shop manual". not a chilton/haynes thing.
this is for your vehicle, 88 pu,
http://www.ncttora.com/fsm/87-4Runne...4runner_88.pdf
rt click, save to hard drive.
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and here is the toyota 4x4 "bible"
http://www.pirate4x4.com/forum/showt...2+differential
your jaw should drop when you read the bible. way more info than a shop manual.........
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good luck,
cheers!
owner 93 4x4 3" lift