00 xj- WON'T IDLE, NO GAUGES

So We have a 2000 xj auto, and a while ago the battery would get weak, low voltage and the jeep would start idling low and begin stalling, so we put a new battery in. It was fine for a week or two, then same battery low stalling/dying. So we put a new alternator in. was good for a day, now same thing plus a no gauges with a no bus warning. Ideas? read something about c301 connector, so we will check that first

What does the voltage gauge read on the dash at idle? With a healthy battery and charging system, you should be around 13.5 to 14.0 volts.

You may also want to "freshen" your engine grounds in case you have a grounding gremlin.

c301 is unlikely the cause. Always start your diagnostics with the basics, they are free and easy. Are all your tune-up parts fresh ? Cleaned the Throttle Body and Idle Air Controller ? Used any fuel injectioner cleaner recently ?

Test the battery, test the alternator, check that you have the correct voltage in the correct places.

As suggested, perform routine maintenance of the start and charge systems. Remove, clean, and firmly reconnect all the wires and cables to the battery, starter, and alternator. Look for corroded or damaged cables or connectors and replace as needed. Do the same for the grounding wires from the starter to engine block, and from the battery and engine to the Jeep's frame/body. You must remove, scrape, and clean until shiny, the cable/wire ends, and whatever they bolt to. Jeeps do not tolerate low voltage, bad connections, or poor grounds and the ECM/ECU may behave oddly until you remedy this.

I had an issue where my 99 xj would refuse to idle and after cleaning the battery terminals/cable ends the problem went away.