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Rough Idle Problems! (still need Help)

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Well My truck has seen better days..


I replaced my o2 sensor, cause the "emission maintenance" Light came on, and I figured that well the light is only a timer, but I might as well just replace it.. and then I found out that the light couldn't be reset without a specific scan tool plugged in? is this true? or do you know of another way to reset this light.


and since I've been having problems with my battery I've been having a very rough idle around.. it jumps around from like 750-250 and everywhere inbetween...anything I should be cleaning out.. or checking on this one.. I have a FSM for a 1992 comanche, but it's a 1990 I have so alot of the stuff in the book I can't use..


1990 Jeep Comanche

4.0L I6



Ohh and my coolant seems to be non-existant, the bottle is empty, and there is all this brown sludge in there.. I've bought new coolant.. but I want to flush the system before I start to fill it back up... any tricks I should know? Where would I want to flush from.. and what could I use to see if my bottle is fine? the lil valve looking thing (metal) ontop of the bottle appears to not have a lid for it? What would be my best approach to flush it and fill the bastard up.

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ok I've been trying to remove the throttle body and I have the IAC and the TPS removed, and I took out the 3 big torx head bolts out.. but there is still something holding it.. and I can't see it. and I want to get it outta the truck so I can spray it down like crazy.. what else could be holding it down?



Also, what would I want to use to clean the injectors? would the throttle body cleaner be enough? or would I want to take them in? How would I clean them?

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ok I've cleaned the S$^% outta the throttle body and the tps and the IAC, I'm still havin that rough idle problem.... I've noticed alot of slack in the cables.. could that be causing me some grief? Now I know with carbs there is an Idle adjustment screw but I can't seem to find one on here.. is the idle non adjustible on TB's?


Also it feel like it's studdering (shaking) at times. When I'm driving it's fine.. it only seems to be at very slow speeds or at idle..


Also there is a wire harness that sits right beside the valve cover (driver side) that get's really damn hot.. and the fuel injector lines ( black things that plug into the injectors) are damn hot too... and seem to be kinda pinched?



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TO FLUSH SYSTEM: Open your bottle cap first. On the left bottom corner (facing truck) of the rad (remove grill insert) theres a little valve to empty the rad. its a b*tch and a half to empty though. I got a little funnel with tygon tubing at the bottom under the valve and a bucket underneath the end of the tubing. It still went everywhere. If you just open the valve you're going to get coolent all over your floor, cross members and just makes a mess. Then undo your lower rad hose then your top, now you can pull it and flush your rad outside of the truck, or get a new one if its crumbling (mine was) Theres a plug on the block somewhere (never did this) to empty it and I assume you also take off the thermostat housing to get a hose in there to flush it, not too sure about that. Just remember that you can't flush the whole system from one place 'cause the thermostat will be closed.

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If this is an '87/88 with the HUGE connector above the brake booster, you need to open it and all the other underhood connectors and clean them with electrical contact anti-corrosive spray. Make sure the little hose going to the MAP sensor on the firewall isn't clogged (I see that a lot on higher mileage rigs)

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