Greetings, all. I picked up a 99 xj a few months ago, and I had it running pretty well, but now I seem to have picked up a few weird issues. Hoping someone here has experienced something similar and can offer me some advice.

The motor and such all seem to be bone stock with the exception of the air intake. I've made the following repairs/updates:

1. Replaced the upstream O2 sensor.
2. Replaced the serpentine belt.
3. Replaced the ignition wires and distributor cap/rotor(99 but it was made before the switch)
4. Replaced the battery.
5. Replaced the fuel pump.
6. Replaced the headlight cover with one from a junk yard(one from junk yard had wiring for fog lights, but my jeep wasn't set up for fog lights from factory. no switch. Just didn't put any bulbs in.
7. Replaced dash cluster to get one that had all proper gauges. Still stock jeep, got from a junk yard.
8. Replaced one of the hoses running to the heater coil.

So after all those parts replaced, the jeep ran fine for a few weeks. Now I'm experiencing two issues. The battery drains when not in use, and it is giving me issues when trying to start. I seems like it is not getting fuel, because if I lightly press the gas when trying to start, I can get it running but it stalls out if I let off the gas. Another thing I've noticed is when I turn on the head lights, the rear windshield wiper and the rear window defogger also turn on. I disconnected the rear defogger switch and now the washer only comes on when switch is turned on.

After the issues started presenting, I replaced the throttle position sensor to see if this would help with the starting/idling issue. It did not help. Also, right when I decided to check in with the experts here, I heard an expulsion of air when I was trying to start my jeep. It seemed to be coming from the very back on the engine bay, closest to the drivers side. Upon inspecting under the hood I found a vacuum line at the firewall that had some sort of relief valve open. Not sure if this is stock or something done after market. I can take a picture if it is helpful.

Anyway, any advice would be very welcome. I picked up this vehicle to mostly keep as an emergency "bug out" vehicle as the area I live in was flooded severely in 2016 so I don't plan on driving it much, but I need it to be able to start for me if/when the chips are down.

It would.

Got a multimeter and test lamp?

IIWM I'd check the fuel pump pressure and/or voltage to the fuel pump. You could have just one big problem (although one big problem could also be obvious) but if those are off it might help to find a starting point.

Did you replace the fuel pump? Why was it replaced?

May not be a "headlight" problem per se, more likely a tail light problem.

Inspect the wiring harness where it passes from the hatch to the body.

What code did the O2 sensor have?

By "headlight cover", you mean the plastic thing?

I can't remember 100% but I'm pretty sure the sensor code was P0420. By "headlight cover" i'm referring to the fiberglass housing that all of the front lights mount onto the vehicle. Turn signals, side signals, headlights, etc. The housing that the grill also mounts onto. When I changed it, I changed the wiring harness as well. New cover was set up for fog lamps, but my jeep was not.


I did replace the fuel pump. Replaced it because fuel was going back into the fuel line and not holding pressure when not running. Also, the fuel pump was very weak when it came to pressurizing the lines. Would take forever to get up enough pressure to start the vehicle when key was in on position. I do have a meter and test light.

I should have added font enhancements to my question, i.e., did YOU replace the fuel pump (and determine the above the issues yourself). One wonders if your old pump was basically OK and this issue has been smoldering for a while.

I took the vehicle to a mechanic to confirm the issues I perceived with the fuel pump. Since I don't feel like dropping the tank I went ahead and paid them to change it once they confirmed it needed to be replaced. It's a mechanic that I've used before and trust. Sorry I still haven't taken a picture of under the hood, weather has been nasty here

UPDATE:

I went to take some pictures this afternoon and I was able to identify the issue with idle/startup. One of the hoses to the throttle body had become detached. I re-inserted it and the vehicle started up and ran, but I feel like I should put a clamp on it. Not sure if that is correct. Here are images of the hose I first thought was leaking air by the fire wall, as well as the one that was out, and the air intake.

As for the electrical, I'm still getting issues with the rear windshield wiper activating when I turn on the lights. Also, I noticed that there is an intermittent buzzing sound coming from the area of the headlamp switch.

Engine compartment, air box has been removed and intake is after market.

Hose below air intake running into throttle body. Does it need to be clamped on?

Line that I originally thought was the source of air escaping the system.

That first hose is to the evap canister and purge control valve. If it doesn't stay on it should be clamped or the elbow replaced. The one with the white plastic end on it is the vent for the front differential. It's high on the body so water won't get into the diff if you go wading.

Agree.

Also, I would recommend using a proper automotive style clamp. While I definitely give you points for creativity, the "clamps" on the fuel line right by the rail do NOT appear to be original equipment.

LOL I had to look at the picture to see what you were talking about. Clothespins...... nice touch. I mentioned in my first post that I changed a hose going to the heater core. I had to change that one because at some point it must have gotten a hole in it, and the previous owner put a plastic coupling in to hold it together. Clamped it down with what looked like coat hanger wire. I'm afraid of what else I'll find over time.