1992 Mazda MX3 erratic idle after warm up

1992 MAZDA MX3
192,000 MILES • 1.6L • 4 CYL • 2WD • MANUAL
Avatar
TEEH1959
  • MEMBER
  • 1 POST
Was having high idle issues (2000 rpm). Replaced ISC (original tested open and sludge was built up inside it).
Now, cold start is fine, runs about 1400 rpm until warm up and drops to 900-1000 rpm. But, the minute you rev it, say to 2000 rpm, it only drops down to 1500 rpm. then after a minute or two it will "grudgingly" come down to 900 rpm again. Same if you put it in gear without hitting the gas.
Also notice the radiator fan is not coming on now after engine is warmed up. All cooling lines are hot.
Tested the TPS and verified settings were within spec. Verified cooling system was bled. Cleaned and verified IAC (top mounted on air cleaner assembly, opened to verify operation and no solder breaks) seems to be working correctly.. Has a new thermostat, radiator, water pump, 02 sensor, exhaust system, belts, timing belt, plugs, wires, distributor, rotor, ISC and clutch.
Wanted to buy a new water temperature sensor (located on top of thermostat housing) but cannot find a single blade replacement. Everything shows up as two blade??
Would the water temperature sensor be causing my problem?
May 22, 2014 at 8:29 AM
Advertisement
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
try cleaning the throttle plate on both sides with choke cleaner and iac hole. first. for cooling fan check items in pic first.
May 22, 2014 at 10:01 AM