Jaguar Forums Helps Turn Jaguar XK8 Lemon Purchase into Lemonade

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Jaguar XK8

When a Jaguar XK8 purchase turned sour, Jaguar Forums members were there to help.

There’s a reason why just about anybody you ask will tell you to never buy an abused supercar. Many of them are going to tell you that because they made that very same mistake once. Once, as it turns out, is enough. However, many of us still fall for these kinds of cars, mainly because they’re cheap. We think that we can fix them up and save a few bucks, but then, things generally turn south in a hurry. As they did for Jaguar Forums member revitup and his “bargain” 2003 Jaguar XK8 purchase.

“I recently bought a 2003 Jaguar XK8 4.2 with 159,000 miles. It had been neglected by the previous owner. The car ran sluggishly when I bought it. But I blamed the hesitation in acceleration on the lack of no knock sensors, which did in fact show up on my computer. One or two other codes also showed up, including a misfire on the #4 cylinder.

So I set out to replace the front suspension plates and misfire before removing the manifold to replace the no knock sensors. I found a bad spark plug on #4 and replaced it, but now the car will barely run and shows 12 codes. I thought the catalytic converters may be plugged. So I removed the EGT on the driver’s side manifold. But that had zero effect. Car seems to idle OK, though it hunts without stalling. So I wondering if this is fuel related.”

Jaguar XKR

A nightmare scenario, indeed. But as zray points out, perhaps the solution isn’t so complicated.

“First and foremost, buy a NEW battery. My ’02 Jaguar XK8 was showing several codes and occasionally a fail safe warning. The battery was strong enough to start the car, no problem. But the voltage was not enough for the computers to operate correctly. Since putting in a NEW NAPA battery, no issues with false code reporting. These cars must have a strong battery or your ownership will be miserable. And keep the battery on a battery tender when the car is not in use for a few hours.” 

Everyone else agrees that this is solid advice. And though some warn of the dangers of buying an abused supercar, it’s obviously too late. So GGG expounds on zray’s advice.

“Good advice from zray on a NEW battery. Partially discharged or failing batteries are the most regular cause of weird electrical and electronic faults on this era of Jaguars. Check for good fuel pressure BEFORE suspecting individual fuel charge/delivery components.”

Jaguar XK8

And since the OP was asking for a list of steps to take in solving these problems, dsnyder586 delivers.

“Step 1- Compression test
2- Fuel pressure test
3- New battery
4- Clear codes and hard reset

This will give you/us a baseline to work with.”

Right now, the OP is working on completing these steps. And it sounds like he’s on the right track. So head over here and follow along as he transforms his Jaguar XK8 lemon into lemonade. And if you’ve got any advice to share, be sure and chime in, too!

Join the Jaguar forums today!

Brett Foote has been covering the automotive industry for over five years and is a longtime contributor to Internet Brands’ Auto Group sites, including Chevrolet Forum, Rennlist, and Ford Truck Enthusiasts, among other popular sites.

He has been an automotive enthusiast since the day he came into this world and rode home from the hospital in a first-gen Mustang, and he's been wrenching on them nearly as long.

In addition to his expertise writing about cars, trucks, motorcycles, and every other type of automobile, Brett had spent several years running parts for local auto dealerships.

You can follow along with his builds and various automotive shenanigans on Instagram: @bfoote.

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