The last time i pulled the codes on my 87 Ranger was when the cruise control died. Hooked up the scanner & in a couple of minutes it flashed a code 29 "vehicle speed sensor voltage is too low." Replaced the sensor & problem solved.

The time before that when the truck was pinging & stalling at low RPM's I pulled the codes again and got a code 53 "throttle position signal voltage is too high" Replaced TPS & that problem was solved.

Time before that when the truck was backfiring something awfull I got a bunch of ignition related codes. Replaced the ignition module & that problem was solved.

YOur 86 & my 87 are not equipped with a check engine light, so the only way to know if there are any stored trouble codes is to spend a couple minutes with a scanner and check.

With your symptoms a code 22
"MAP sensor signal voltage out of specification
would be handy













Or how about a code 33 EGR valve not fully closed.