3.0 rough idle
Post Fiend
Joined: Jan 2000
Posts: 5,860
Likes: 4
From: Metro Detroit (Redford)
3.0 rough idle
Wifes '92 Aerostar with 3.0 and 91,000 miles has a rough idle, but smooths out when air conditioner is running. I have new cap, rotor, and wires recently, but the plugs have somewhere around 40,000 miles, thought they are the platinums. Runs great on road, lots of power, so I would think if the plugs were that bad it would run poorly at speed. Ran Valvoline Synpower complete fuel system conditioner and injector cleaner through on a couple tanks of fuel. Also put dry gas in tank. Still the same problem.
Posting Guru
Joined: Apr 2000
Posts: 1,746
Likes: 4
From: PNW
3.0 rough idle
Seems to me there was someone on this board who had a similar problem and it turned out to be just a low idle speed setting. When you turn on the AC, the IAC opens up to increase idle speed due to the load of the AC compressor so that's probably why it runs fine with the AC on.
Post Fiend
Joined: Jan 2000
Posts: 5,860
Likes: 4
From: Metro Detroit (Redford)
3.0 rough idle
Thanks much. That makes perfect sense to me. Wonder how you adjust the idle speed?
INLINE SIX POWER!
'95 F150 XL
300 Cubic Inches of Low RPM Truck Torque! And twin-I-beams too!
"Drive a stick young man! There'll be time for automatics when you're old and unable."
INLINE SIX POWER!
'95 F150 XL300 Cubic Inches of Low RPM Truck Torque! And twin-I-beams too!
"Drive a stick young man! There'll be time for automatics when you're old and unable."
Post Fiend
Joined: Jan 2000
Posts: 5,860
Likes: 4
From: Metro Detroit (Redford)
3.0 rough idle
Last night I tested your theory. While I don't have a tach, I let it idle and then turned off the air. The idle went rough. I gently gave it a little throttle and the idle smoothed right out. Just a tweak of the throttle stop should do it. Thanks
