My '91 3fe FJ80 I've owned since 2012 has developed a high idle that I'm just beginning to diagnose. I'm looking for any useful insights to make solving this easier. Here are my symptoms:
Very high idle:
@jonheld or other 3fe experts...
Am I missing anything obvious? Is the air conditioning issue pointing toward a culprit that I'm not seeing? Should I adjust my priority of repairs, or add another step?
Very high idle:
The truck idles at 1500-2000 RPM's regardless of temperature
Things I've checked (vehicle is desmogged)
Check engine light is not illuminated
Visually checked vacuum hoses
Visually checked intake tube (which was replaced a few years ago before they went NLA)
Tightened / replaced clamps on vacuum tubes, and intake tube
'Golden screw' is all the way in
Throttle cable and kick down cable have a little bit of slack when the throttle cam is all the way closed
Valves were adjusted 10k miles ago
Timing adjusted 10k miles ago
VC gasket, and associated bolt / PCV valve gaskets replaced 10k miles ago
Things I have yet to do (in order of priority)
Check with vacuum gauge (where's a good spot to hook one up? What reading should I expect?)
Check vacuum lines with starting fluid (or similar) to find potential leak points
Remove and clean TB
Remove and clean IAC (which does click when the vehicle is shut off)
Test TPS per FSM procedure
Check dashpot throttle stop (I can't imagine this would get messed up on it's own)
Severe bouncing idle when starting the truck with the AC on:I have not seen this discussed on 'mud, and I'm wondering if this will point to the issue. If I start the truck with the AC off, it will idle high. If I start it with the AC on, it will bounce rapidly between 1k and 2k RPM's until I put it in gear. The AC does work, and is not overcharged.
Weak acceleration until 2700 RPM's:I'm getting the typical weak acceleration until 2700 RPM's normally associated with a vacuum leak
@jonheld or other 3fe experts...
Am I missing anything obvious? Is the air conditioning issue pointing toward a culprit that I'm not seeing? Should I adjust my priority of repairs, or add another step?