What may cause a 1986 Mazda pickup rebuilt carburetor to not run right and cause an uneven idle?
Well assuming the carburetor is set properly idle wise with a
meter and all the normal tune up things are in KNOWN good
condition.My suggestion is clean the egr valve under the carburetor
with carburetor cleaner and note the position of the gasket on it
for reinstall purposes.When cleaning it use some sand paper or a
small brush to remove the carbon buildup.It has one vacumm line,one
electrical connector going to it with 3 ten millimeter bolts that
hold it on.If the idle is still crappy I would suggest a new map
sensor which is mounted on the passenger side fender with a vacumm
line and electrical connector on it.And the tune items like
plugs,wires,cap,rotor button and even the oxygen sensor are
critical.Hope this gives you some insight into the issue.