I have a 98 xk8 with no problems. My buddy also has a 98 xk8 and here is the problem he has experienced - while driving at freeway speeds, the amber "Fail Safe Engine Mode" light came on. There was no change in performance of the engine. His mechanic said it could be the gas cap or throttle body. A new gas cap was put on the light went out but only temporarily. Upon starting the car, the Fail Safe light is off, but continues to reappear after driving several miles. The engine maintains full power when the light comes on. His mechanic said it could also be the throttle body and quoted a price for a new throttle body at $3500. He has a used throttle body available for $600.

Any ideas what the problem may be and would it be wise to replace the throttle body without further diagnosis? As far as I know it has the original throttle body which was not replaced through the recall.

 

Do you have a check engine light or OBD code P0121? I would look into this first http://www.gusglikas.com/AutoRepTB.htm

 

The big 'replace the TB' issue was that the engine would shut down at highway speed and then would restart at the side of the road.

While it could be the TB I would exhaust a number of other things before throwing the big bucks at it. No CEL? The FAQ sticky at the top has several 'restricted performance' discussions. My first introduction to that issue turned out to be splits in the bellows section of the duct between the MAFS and the TB.

 

qwakwak,

This may sound odd, but I brought my 98' XK8 in for the same reason. I would drive approx. 15 minutes and the Failsafe Engine Mode would appear. I posted this on the site and it was suggested (Thank you Gordo) that I have the codes checked. Before the dealership even ran the codes, the service manager said it is likely the brake switch. I was skeptical, however he was correct. It has not happened since. Good Luck.

 

MicksJag - Thats what the problem was in my buddys 98. They replaced a relay = problem solved. Approx $350.

 

I have seen several posts referencing the brake switch yet we often overlook it. Strange little switch! I wonder how many times it has come up in the past and why? $350.00 @#!%@^@^#^^^?

 

The work was done at San Jose British Motors -diagnosis and switch / relay replacement. Dealer servcie rates in SF bay area are slightly over $100/hr.

 

And I thought I lived in a high rent district in northern Virginia

 

I wouldn't do anything else until pulling the ECU codes. A common cause of this light is a bad knock sensor. But there are others and until you have some idea as to the cause, you have no direction at correcting it.

 

My knock sensor produced a restricted performance and was hard to find.

 

It's located on top of the engine under the intake manifold.












Just joking!

 

Is this what you are looking for?

 

Good job Gus!

 

gus, any chance you can try to make your 'images' larger? I've noticed some small ones, difficult to see details in it.

Just checking...maybe something you could try for next attachment.

 

OK! Fine! I will do better the next time. Only kidding but I did think about that. I am concerned if it is larger it manages to take a lot of computer space and manages to slow things down. How about printing one and see what it looks like. Open it, do a right click on the picture then select print.

 

Hard drive storage is cheap, don't worry about server space.

Images are limited to file size, not dimensional ones. So, big images will be 'reduced in quality' to meet size, however, if you look on the attachment screen, pdfs can be MUCh larger, so I like to use that when doing large multipage JTIS clips.

Give it a shot, i'll keep an eye on your posts...see if I approve. lol

 

Matt - can you go into more detail about the attachments. I'd love to post a larger, more flattering pic of my car (something like the one you use), but the little thumbnail is all I could get by the size limits. You are a photographer - how to go about it? Thanks, DaleD

 

I just use Windows ZOOM !

 

DaleD, go HERE to read and practice.