Happy New Year!

Going off the advice of this forum I bought and have been trying to repair a 98' XJ8 (103K mile). I love the way the car feels, but getting frustrated by nagging little issues. I am currently dealing with what I think is an electrical issues as several things are popping up. Please tell me what you think!

Fuel Level Gauge Indicator works intermittently- Sometimes is shows full and other time empty no matter how much gas I put in it. I even replaced the Fuel Sending Unit.

Driver Side Window - does not work. I followed advice on this forum and rebooted my electrical system by unplugging the battery and it started working again for just one day.

Brake Lights work Intermittently- Causing a gear shift problem whereby I have to use the manually override method to get it into drive. I turn on my lights and tap the brake until I can hear a little noise coming from the shifter...then my lights and shifter work. I checked the 5 and 7 15amp fuses (Okay).

I also get Intermittent (every two weeks) error codes that makes the car idle high, goes away after turning it off for a few minutes. 1. Fail Safe Engine Mode, 2.Traction Control Fail 3.Stability Control Fail

Lastly, Check Engine light is on after being cleared several times-giving a P0453 Evap System Pressure Sensor code.

This car has a lot of wonderful qualities, but it also has it share of quirks. I'm thinking I need an auto electrician as I do not have the know how nor the testing tools to check things out. Do any of you knowledgeable owners or mechanics have any advice before I proceed?

Thanks for any advice!
98' XJ8

 

I would at least try cleaning up the grounds. The big three are the battery strap and the strap under the RH side attached near the bell housing - I replaced both of these with regular heavy duty cable instead of the braided stuff. The third is the cable connection at the "false bulkhead". This is where the cable comes to a terminator and connects through a nut and bolt connection. RH side under hood. These cars are sensitive to current and a bad connection or ground can cause all kinds of things to light up.

 

I'd try a new battery as well as following checking the grounds before you start hunting around, these cars are super sensitive to voltage.

If the battery is below 12.5V all sorts of things happen. Get the one in the car tested, it might be failing and being cold will really test a marginal battery..

 

I replaced the brake light switch and now the lights and gear shifter work. I also took the trunk apart to find that the Evap connecting wire was left off when a bootleg mechanic shop replaced the fuel filter. I reset the codes so lets see what happens. I'll check on the straps and battery as it had to be charged a couple times since I've had the car.

Thanks guys!