i also have a 1988 toyota 4runner 5sp/22re fuel injection when it rains real hard and theres alot of standing water on the roads ,mine has run funny jerking idling hesatant,until i romp it and dry something out (i know i have replaced dist.cap all that and wires but believe it or not old shade tree mech. told me to spray my wires and dist. with wd40 when it rained and it actually did help?why??But also later sortam same kind of thing was the map sensor/mass airflow sensor(not sure on name) but its inbetween air filter box and throtle body,should have wire commming out ,be prepared to spend around 200/just info good luck