- Joined
- Oct 27, 2020
- Messages
- 122
- Reaction score
- 65
- Points
- 28
- Location
- Oahu, Hawaii
- Vehicle Year
- 1991
- Make / Model
- Ford Ranger
- Engine Type
- 4.0 V6
- Transmission
- Manual
- 2WD / 4WD
- 4WD
Im currently having a similar issue with my rig as well, however, doesn't appear as bad as yours. My truck will idle high when I come to a stop light or have it in neutral when warm. Idles at about 2000rpm. But not always! Sometimes (rarely) it will idle perfect around 800 rpm. So my issue comes and goes as well. Motor runs smooth as silk other than the high idle.
I performed all the same checks and replaced most of the sensor: IAC, MAF, TPS, PVC, & O2 (only one on my truck). All to no avail. Have not changed out the throttle body yet but its next! No vacuum leaks to speak of. Im not too certain that the new IAC is doing its job since I get no change in rpm at idle when I disconnect the pigtail. Is it supposed to shut CLOSED when disconnected? My truck was originally an AUTO but I converted to a MT but did not swap out the PCM. I'm told that this is only good for a few hundred RPM so didn't want to spend the $$$ just yet.
1991 XLT 4x4
4.0
Auto to manual conversion
I performed all the same checks and replaced most of the sensor: IAC, MAF, TPS, PVC, & O2 (only one on my truck). All to no avail. Have not changed out the throttle body yet but its next! No vacuum leaks to speak of. Im not too certain that the new IAC is doing its job since I get no change in rpm at idle when I disconnect the pigtail. Is it supposed to shut CLOSED when disconnected? My truck was originally an AUTO but I converted to a MT but did not swap out the PCM. I'm told that this is only good for a few hundred RPM so didn't want to spend the $$$ just yet.
1991 XLT 4x4
4.0
Auto to manual conversion