How do you set the idle - 1987 Chrysler Fifth Avenue

Most older cars had 2 adjustments , a air screw for enrichment and throttle screw for engine idle speed, later models did away with the enrichment screw, to adjust set idle screw to 600 rpm, adjust air mixture screw to fastest rpm , reset idle screw to preferred idle speed.

Bill, you could possibly have a vacuum hose leak. With motor running, open your hood and listen carefully for a hissing sound. If you hear one, try to pinpoint where it's coming from.

thats what happens when you change the set screws,idle set screws will bring it to an idle,when you are at that 1st point,where it idles fine,stop,your idle set screw is done

adjusting idle will be a big mistake,,,,tps ,trottle plate, map will be misadjust too.
Idle is set by iac valve. you have to find out what cause idle to change.

fast idle speed screw, works off the fast idle cam which the choke adjustment sets, it works together by linkages. This is the raised idle speed setting you need to keep a cold engine running. First you set the idle speed by the idle speed screw with engine at normal operating temperature. Then you set the linkage up so the cam is on a raised step, throttle will be held on that raised step. then you can turn the idle speed screw to get idle at about 1500-1800 rpm. Now when you start engine cold, choke will set the fast idle cam on that raised step- when engine starts and runs it should be running at your fast idle setting. That's how it supposed to work, you just have to get everything adjusted right. I hate carburetors, they never stay adjusted right. Considering their complexity and small mechanical parts, no wonder.

Could be a faulty idle air control valve.
The computer controls idle speed by regulating how much air enters the throttle body thru the valve.
You could unplug the valve when the idle speed is close to normal, then shut the engine off and restart to see if the idle speed is still in the same place. Unplugging the valve will also set a trouble code and turn the warning light on.

Start with the idle needle screw first, the idle mixture screw. Seat it all the way in, first-don't overtighten and damage it, just seat it lightly, and back out two full turns. Run the engine and set the adjustment by ear to get your best lean idle: start turning the screw in (clockwise) 1/8 or 1/4 turn at a time till engine stumbles, dies, or runs rough. Keep the engine running, and turn screw out (counterclockwise) a little at a time till you hear the idle dropping. Now between those two settings is your best lean idle. Turn the screw in, a little at a time and wait for engine to respond, tiill you get the highest idle speed. Now set the other idle screw, curb idle, to the idle setting for your truck, probably about 700 rpm. You can move back and forth between the screws to get the best steady idle. Just don't over do it on the idle mixture screw.
Good luck.

Wow you change everything, TPS was right thing to do and so is the Idle air control,and MAF and EGR, fuel pressure, So it idles high then some one tried to defeat the stall in gear? Even if there is a vacuum leak creating high idle it shouldnt stall in gear, , What color is the transmission fluid? when in gear in drive step on the acelerator pedal to maintain idle to prevent car from stalling. Just enough to maintain let say 1100RPM. Is there a vibration? I mean a torque convertor vibration. Torque convertor stall are common an GM and Nissan,very rare do I ever see it on Ford. I really belive the IAC is not getting power and is just been adjusted manually, cause I know its not the transmission, At idle in gear pull the plug on the idle Air control does it change in idle setting? If it doesnt change in Idle setting the adjustment that was use to control the setting lower the idle to its normal setting. Plug the idle air control in then.The idle air should change the setting. If it doesnt its not getting the signal it should.

moving the distributor will alter the idle because it makes the engine run easier or harder

Forget the idle and set the distributor at 10 degrees BTDC
now that the timing is correct then adjust the idle speed at the idle screw on the carby

the fast idle is set when the choke is close to set the cam on the HIGH STEP. turn the car off hot, now pull the accelerator back and close the choke with your hand, now let the accelearator back to idle, now the idle is on the high step, carnk the car and set the idle speed, the base the fast idle screw is against the step on the pass side of carb.