I am in dire need of advice!!!!!

Last year, I bought a 1997 XJ6 with 155K miles on it, body is decent shape, ran rough, but was able to smooth out with new ignition coils. I drove it all last summer and through the winter. Without a doubt one of the best cars I've ever driven in my life.

Mid April into May, I started having issues. The car has been off the road since then because I haven't been able to figure out what is going on.

As you're driving (55-60 mph), once it is up to normal operating temperature, the car will completely shut down, complete power loss across the board, even the OBD scanner loses connection. After a split second, the car will then return to life. If you try reproducing the same circumstances while parked, the car will not come back to life on it's own.

Also, since this occurance has began, it is also eating batteries like you can't imagine. I had a brand new, 900 CCA rated battery, and it's now completely dead. The battery itself was not even 4 months old.

I am hoping someone has suggestions as to what to look at and how to possibly fix, because if not.......I don't want to part with it

 

Wow. Not a lot of ideas here but potential water damage may have caused widespread shorting? This may explain the battery draining possibly. Just guesses this sounds very odd and dangerous.

 

Two things I would look at first.

1. ECM Controlled Relay - Front engine compartment (see attached). Swap it with another relay for testing purposes - say the Air Con clutch. See if problem persists.

2. Check Positive battery cables on bulkhead (one left, one right, follow thick cable from under bonnet fuse boxes back to bulkhead) for cleanliness and security. If possible do some voltage readings at battery and then at fuse boxes under bonnet to confirm no voltage drop.

 

The alternator would have been a big question mark after the first battery.

State of the charge light is immaterial.

 

A tip for finding battery drain remove positive OR negative terminal from the battery connect a test lamp or low wattage bulb in series with removed terminal (connect one wire to the battery post and the other wire to the loose cable end) depending on how big the drain on the battery is the lamp will light dim or bright, now unplug components or remove fuses until the lamp goes out, I would start with the alternator the rectifier pack inside is a prime suspect in battery drain issues, Good luck.