Car ran great but after sitting overnight it will start but will not idle.
Starts right up and runs as long as fuel is supplied with the pedal but
stalls when the pedal is released. Seems to have a lot of slack in the
throttle cable at the throttle body but I see no mention of throttle cable
adjustments or springs in my repair manual. What could have possibly
happened while parked overnight ? Any ideas ?
The most likely cause is a gummed up IAC (Idle Air Control). Easily removed
and cleaned or replaced if necessary. Look for the silver cylindrical object
attached to the side of the intake manifold by two hex head screws. There
will be one electrical connector on the end. Take it off, look inside. It
will be black and gummy in the air passages. You can try cleaning it with
valve body cleaner or just replace it (~$60).
Ford IAC failures seems to be an epidemic. I wonder what has changed in the
last few years? Ford has been using basically the same style IAC for at
least 15 years. I never had one fail until two years ago. However in the
last three years my family members have had 4 fail (1 Grand Marquis, 1
Mustang, 1 Escape, 1 Ranger). Plus the guy next to me at work had one fail
on a Grand Marquis as well.
You never mentioned which engine you have.
My 3.8 v6 had an idle from 0 to 2000 rpm and it was easy to fix. The idle
speed solenoid sits on top of the air inlet. and has a couple of wires going
to it. In my case the electrically operated plunger was sticking in the
Mine also had a absolute stop screw that prevents the throttle from closing
completely. As a quick fix I disconnected the idle solenoid and adjusted the
positive stop 2 or 3 turns and it idled at 800 to 1000 rpm all week just
fine. I put it back after I picked up a new solenoid.
It was definately the IAC. I pulled it and cleaned it with Carb and Choke
cleaner, re-installed it and checked all connections. It started right up
and idled normally. I'll just buy another and replace it since my wife
drives this car and I don't need any emergency phone calls from her. It
took a few minutes to find the AIC with it being behind the throttle body
making it a little tough to get to. Bob, you're right, I did forget to say
the engine is a 4.6 lt. I appreciate the help from all. Glad I found this
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