Hello Cats, my amber engine light came on tonight, with no fault. I noticed a bit of a ruff idle when I started her up but it went away. Then the engine light came on. She's driving fine. Not sure what's going on. Any thoughts???

 

Probably a misfire issue that went away. Almost the exact same thing happened to me the other day. My daughter had just gotten her learners permit and as we were leaving the DMV I let her drive the Jag. She started the car and it was obviously missing on a cylinder or two. Every once in a while that happens when I start the car, but I usually just tap the gas pedal and it goes away. But in this instance I was making sure she had the seat adjusted properly, the mirrors adjusted, seatbelt on, no cars behind us, etc. It idled rough for 30 seconds or so before I told her to give it a little gas in park. Then she said "What's that light mean?" I looked over and the check engine light was on. Fortunately I had my handy dandy bluetooth OBDII tool plugged in and I pulled up the DTC codes on my Android phone. I saw that it was "misfire" something or other. It was running fine at that point so I just cleared the code. That was 5 days ago and it hasn't come back.

I'm not saying that there's nothing wrong with your car, but if it is idling fine now then you probably just need to reset the check engine light. If it idles rough when you start it just give it a wee bit of gas.

I've learned that these cars can be very finicky. For some people little things like a check engine light after a rough idle may freak them out to the point that they want to get rid of the car. That works in our favor, though. We can buy beautiful pieces of artwork that haul *** for a fraction of what a new one costs.

 

How do you clear the code Sam?

 

Hey Bass, if you need an OBDII tool I've got one I'll sell you cheap. I don't need it any more now that I have Torque installed on my non-Apple phone.

Seriously. Just PM me if you're interested. $40 including shipping. They are selling on eBay for anywhere from $45 to $89 plus shipping right now. It's an Actron CP9135. Here's a pic:



I put the dogs in the pictures to show the size of the device. The dogs are Great Danes so as you can see it is huge! Shipping alone will probably cost me $40. The dog on the right is a Pirate. He lost his eye in a sword fight with Johnny Depp. Normally he wears an eye patch but he's feeling casual tonight.

 

If you go to any auto parts store they will read the codes and clear them for you for free. You can also do it with that OBDII tool I showed in the prior post. I'm not sure if a misfire will go away on its own. It might, but most codes have to be manually cleared.

 

Personally I think an OBDII scanner is a required tool for anyone who is the least bit handy. There is so much info you can get from them, and you don't have to take the car to the dealer or the auto parts store. I'm not trying to talk you out of buying the one above, but if I was you I would buy one of those bluetooth tools I posted in the other thread and get that app for your iphone. It will give you much more info than the Actron tool above.

 

the rough idle at startup is a classic vacuum air leak, in my experience. There are various locations where brittle plastic breather lines, that air pipe, hardening/shrinking o-rings on the norma fittings leak due to age or cracks.

 

That may be what's wrong with Bass' but I'm pretty sure on mine it has to do with that bad check valve in the fuel pump. It only happens when I have the long crank time. As soon as I give it a little shot of gas it smooths right out.

...hmmm, now I have another thought. Where is the fuel pressure regulator located on a 2003 XK8?

 

I didn't even know you were having rough idling issues Rev. I knew about your long crank times and that fuel line return you've been chasing...but that's it. I'm getting pretty familiar with the 'air' part, you with the fuel, we should pair up, go on tour, travel the country troubleshooting everyone's misfire/lean/rich codes...for a small donation of course

 

My rough idle lasts maybe 2 seconds at the most unless my daughter is starting the car. All it takes is a quick press of the gas pedal to get it to go away, so I'm sure it's a fuel issue. I don't even consider it a problem. It's just a part of that whole check-valve problem. I am so dreading pulling the fuel tank.

 

I think you're doing exactly the right thing in letting your daughter learn about driving on a less-than-perfect car. I'm old school and nothing irks me more than kids (and adults) that know nothing more about their car than the color.

Granted, over the past 20 years a lot of the excitement has been drained out of motoring, especially on the mechanical side, but everyone should know the basics.

I towed a kid the other day but ended up leaving him stranded at a gas station when he expressed absolutely no interest or aptitude into even the most meager diagnosis of his simple situation. Given that, I figure he was fair game for the station owner.

 

Whoa! Hang on a second! I never said anything about letting my daughter learn to drive in the Jag! I let her drive it once on the day she got her permit. I was rewarding her for getting her permit. She might never drive it again.