Hey y'all, have a silly question. Ok here's go's. I have a 2002 XK8 4.0 BEEN having trouble with codes p0171 and P0174. Trying to track down vacuum leaks. My question is, is it possible for the oil filler cap and the dip stick.sucking in air ? I've noticed it has o- rings around each one of those .and the oil filler cap is showing oil around on top of the valve cover .other than that she's running fine. Just turned 70,000 miles.

 

Doug,

I've moved your question from New Member Area - Intro a MUST to XK8/XKR forum. This is the place to post technical questions about your model.

Graham

 

They have both been identified as sources of leaks.

 

Well that gives me some Hope! Thanks you very much.

 

The commonest cause of P0171 and P0174 is air intake leak between MAFS and throttle body. Have you definitely eliminated this?

Graham

 

Leaking VVT O-ring seals will also cause the P0171 and P0174 codes. A relatively easy and inexpensive replacement job. These two seals bake in the engine bay heat and tend to get hard and brittle within just a couple of years. My wife's 2006 XK8 is currently on its third set of them....

 

Yes ,thanks Gramm

 

Yo,jon89 sorry don't quite understand what the VVT O- RINGS ARE

 

VVT seals Part# AJ82856

 

Rocker cover valve seals ? Is that the ones under the valve covers? Cause mine are showing alitte oil on top of the spark plugs.just keeps getting better.

 

If you have oil present on the spark plugs, it's only a matter of time until coil unit(s) short and cause a misfire. Replace the VVT seals and if the cam cover gaskets and spark plug boss seals are leaking, they should be replaced too.