I had the exact same Issue for ten months 5000 miles, replaced all parts as you did...drove me crazy..Then found fauaty fuel pressure reg. would from time to time allow raw fuel to drip into T/body..It has now been two months and 1000 miles still OK...I'm not an advocate of just throwing parts at a problen BUT the F/P/Reg is about $150.00...The only other poss. Is the ECM???I think...

 

Thats strange as far as I can see the fuel rail and throttle body have no connecting bits at all. Fuel rail dumps fuel into the inlet manifold via injectors which are located after the throttle body. Someone please confirm ???

Anyway I did find a bolt lying on top of my gear box which I think is the top bolt for the EGR value i.e. one of the two that connect it to the inlet manifold elbow. I can feel one bolt head but not the other theres a hole where it should be!

So I'll be taking the throttle body off, EGR Value and EGR pipe and give them all a good check and clean!. As I'm guessing air could be drawn in under acceleration even though when I had the engine running and sprayed flammable fluid down there no change in RPM or STFT was detected.

UPDATE
Yes it the EGR bolt I have the throttle body and EGR value out now giving it all a clean. It would have been leaking air into the throttle body so lets hope the car runs better after all this cleaning.

I was so luck that it didnt roll of the top of the gear box and onto the ground!!

Not sure how it worked loose as the other one was tight and so were the bolts got the EGR tube.

Thanks
Simon

 

This reminds me of a problem I had with my 99XK8 last April. First off running lean so my indy changed the MAF.. It then threw rich both banks so they changed the induction hose. Still rich(both banks,restricted performance) so yet another visit and they downloaded new software into the ECM. Still no improvement and $1400 down they then tried to blame the throttle body($2400). At this point I decided to "get back on the tools"- it had been a while :0)
I then noticed that it only seemed to flag restricted performance on the over run and when it was warm, which suggested heat expansion of something. Checked and found two spark plugs had worked slightly loose(one on each bank) - retorqued them all and no problems since. Always pays to check the basics first

 

Oooch yes I check my spark plugs and found a few loose, 2 were hand tight. I've fixed that but same problem still existed. Now I have a genuine Jag MAF (tired 2 Chinese ones first long story ) so fingers crosses.

I also decided to track down where the bolt I found on top of the gear box was from. Just finished taking throttle body and EGR valve out (bolt was top one from EGR valve) cleaned all elec connections and throttle/EGR valve. EGR valve between inlet elbow and valve had been leaking air (cos missing bolt) so I'm hoping STFT/LTFT/Rich condition will be fixed. But who knows!!

Reset ECM again. Need to take it for a long drive but its raining here in CA so will wait till tomorrow.

 

OK new MAF from Jaguar got the MPG back to 14.5 MPG and putting the bolt back in the EGR value and good clean of throttle body has got me to 17.5 MPG.

Bank 1, 2
STFT (mean) 0.38% & -0.56%
LTFT (mean) 5.85% & 4.67%0
after 15 mile drive on freeway @ 70 mph

I have never got that MPG. Jaguar dealer did the EGR pipe back in 2004 just after I bought the car my guess is the bolt has been loose since then as the bolt head was rounded, so they must have removed it. That really sucks loosing 3 MPG for 30K miles ($1200 in fuel wasted)!!

Thanks Jag dealer !!!

Car now reads ready for emissions test even though the Catalyst test has not completed all others have. Component test says pass even though I still have the TID $0A failed.

$0A $00 EGR system flow malfunction (GA changing rate high)

Anyone any ideas what this may be ? See attached docs

Thanks
Simon

 

Strike fuel Pres. Reg...MIl lite just came back on..P0172...P0175...rich run both banks??? You are correct on the the FPR can not dump inti T/B...

 

Ok so far no issues and car passed it CA emissions test with flying colours!! So lets hope for 30K problem free driving (it ows me after all the items I've fixed replaced see my post https://www.jaguarforums.com/forum/x...my-list-87158/ ) which at my annual rate will be 10yrs!!

Simon