Hello and welcome to jeepz.com.
That problem of excessive water coming from the a/c moisture drain sounds like a leaking heater core . Guessing the coolant consumption is excesssive . A radiator pressure test will confirm that but as long as your seeing colored liquid draining . It's sure to be coolant and that would mean a heater core . It's possible to remove the heater/a/c module from under the dash to perform this swap but I did it and preferred removing the dash to work more comfortable . Luckily a Cherokee dash comes off a lot easier than a grand Cherokee . There screws in tight places that dash removal just makes it easier . Besides , if your a/c is working , why disturb it . Remove the dash , remove the top cover and swap the heater core without disturbing the a/c evaporator. It's involved but not the worst job I can think,of. Just tedious. as far as the stalling problem , just wondering if it's related to the coolant loss or a drivability problem . If the engine temperature is running too hot , the PCM may be shutting the engine down via the auto shut down relay . Low coolant and/or low oil will trigger the ASD if the PCM picks up on it. That's to save the engine from destruction . Looks like modern technology has advanced since the idiot light , thank goodness. Meanwhile , things to check also are drivability items that could contribute to stalling . In your case , the engine stalls warm engine . That means the PCM is in closed loop running off its sensors . If the coolant temperature sensor is picking up a hot engine engine , the ASD kicks in and cuts the ignition . Let's say the coolant system is fixed and no more leaks and it still stalling . Now it's a drivability problem which can send you climbing the money tree . As you've stated , you don't want to be a parts changer and no one should . Changes what's bad , not what one would think MAY be the problem . This is when we've got to start simple . If the engine starts and runs well until the stalling begins , that could be many things but got to start somewhere . Does the engine start and run at a higher rpm than at a warm idle ? The idle air control motor may be working but the chamber and IAC motor pintle may be gummed up. The jeep was sitting a while so it's worth a look and a can of throttle body cleaner . When the cleaning is done , see if there is an improvement. Hey , before I forget to ask , any dtc's ( diagnostic trouble codes ) stored ? Any check engine light ? I would expect so but that needs to be checked. There's no EGR valve so that wouldn't be the case here . Chrysler took care of that with fancy camshaft dynamics lobe separation angles take care of the time combustion occurs so volumetric efficiency is all taken care of in that department. Only know so much of engine physics so we'll end the engine theory lesson there. Jeep sitting for quite a while . Wonder if the catalytic converter a little clogged ? From your description of how well,it runs until it stalls , dosen't sound like it . This problem is saving you money already on haircuts since it's got you pulling your hair out . A scan tool would be helpful right about now but I don't own one either . It's all test lights and multimeters for me. Like to know if an O2 sensor is lazy and not switching rich/lean so the fuel injectors aren't doing the right thing and may be leaning out when the engine gets a little hot due to the coolant loss problem . Not to mention the coolant pressure is dropping when air displaces the coolant when leaking out. That will promote detonation which would trigger a knock sensor to retard timing . Only problem is I don't think the '98 4.0 liter has a knock sensor . I got a spare 4.0 out of a '98 GC and don't recall a knock sensor on it. Just more food for thought , clarification and process of elimination . So whys this jeep stalling ? See if a trouble code has set . If so , try to erase it or if more than one , erase them and see what comes back . Those are hard codes that means are still existing faults for problems still not fixed. Let's not fall into the trap of parts changing . I know you know that. For example , just because an O2 sensor reads lean , don't mean it's bad and must be changed . Has to be read if it switches rich/lean ( cross counts ) . A lean condition may mean a vacuum leak . I takes on these 4.0 engines are common. Think I'm working on one in my '92. You can only torque but so many times. So , fuel system pressure good ? Maybe , running well but should be checked since a drop suddenly on a slowly failing pump can mean stalling . But that's extreme . Look for dtc's , bypass the heater core for a test only but the fix is a better option . The heater core actually is a heat exchanger and if bypassed will contribute to a hotter running engine . I would start with the obvious ( the heater core) and after the air is bled from the cooling system , see what happens next . Don't want you to start thinking o2 sensors , coolant temperature sensor , etc. until the engine cooling system is stable. Also , the idle air control and chamber too. Start small and let's see what happens there. Hope this helps and looking froward to your post(s) soon as you can. There's enough work as you know , may be a while ? These problems can sometimes turn into a volume ( already wrote a book now ! Lol) so we'll see what's next. Best of luck and thank you for your membership here at jeepz.com.
p.s. - JPNinPA beat me again . Lol . Got to get home earlier or learn to type faster. He's got a condensed ( thank goodness) diagnostics procedure WELL worth following .
