Why won't my1991 Jeep wrangler idle when engine is cold?

SOURCE: Stalls when engne warms up

Your ECT (Engine Coolant Temp) sensor is bad. What's happening is at cold start it richens up the fuel mixture and as it warms up the ECM thinks it's still cold and essentially the "choke" is still on. Also check your coolant level. If you don't have enough coolant in you engine/radiator, the ECT doesn't know what to do so it thinks it's cold.

SOURCE: 98 jeep wrangler no heat

Try this disconnect the heater hoses from the heater core use a hose to backflush the core. Then reconnect and try again.

SOURCE: 988 Wrangler will not idle and runs rough

check vacuum lines would be the first thing i would look at. try taking some carb cleaner and spraying the lines and if you get a change in idle you have a leak

SOURCE: Heater blows cold air when idle

Sounds like you may have a partially plugged heater core. You could flush this out separately, from flushing radiator & engine block. Diconnect heater hoses going to your heater core and clamp off, so not to loose coolant from engine. Now hook up separate hose to one side of heater core pipe and flush out with typical garden hose. Repeat procedure on both heater core inlets. Reconnect original heater hoses and test difference. You may have to add an additional litre of antifreeze. If this don't work i suggest changing heater core. Good luck.........Ron.

SOURCE: '00 Jeep Wrangler with no heat and AC not blowing

Ok, if you are trying to use your AC and its not turning on, odds are your refrigerant levels are low, the system will not turn on when low fluid levels are present so the system doesnt burn up the compressor.

If your blower motor is not operating, you may have a fuse blown that needs to be replaced, or the control chip that plugs into the blower motor (for fan speed settings) has burned up (easy fix).

If your climate control is not throwing out heat when you change the settings to hot, you have a leaky vaccume line and the vaccume pressure is not strong enough to open or close (depending on setting) your blender box. Although typically when a vaccume line springs a leak you will have issues with your selector switch as well (defrost, vent, floor)

Also pay attention to your temp gauge to make sure the thermostat is operating properly, and the engine is not over heating ro getting excessivly hot! If it is, then you need to replace the thermostat ($8 part)
and go from there. Also you should check your heater core, if it gets clogged or has restricted coolant flow, your system wont have the heat it normally did (if any) when it worked properly.

This is just a quick summery of the area's you should be looking into for the problems you are having! thanks for using Fixya.com and good luck, I hope I have helped make resolving your problem alittle easier

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