XKR poor acceleration

[jipo999jim]

Lately my MY 2000 XKR is poor on accelaration.
At first I thought traction control is cuttiing in, but the traction control light does not come on and even with traction control switched off the problem is the same. I am unable to provoke any wheelspin.
There is a clear flat spot in the range 2000 to 4000 RPM at full throtlle. It looks like it is running out of fuel or is misfiring. The engine fault lamp does not come on.
Air filter, fuel filter and sparkplugs were renewed 24000 km (15000 miles) ago. Car has now 130 000 (80 000miles).
Any ideas ?

[jagtech]

I would check the air flow meter it can give an incorrect feedback to the ecm causing low power
Good Luck!!!

[jipo999jim]

I removed air flow meter and it is not contaminated, I did not replace it yet.
Testing the car again it seems to run out of fuel only when at full throttle. At medium or 3/4 throttle it picks up speed well.
I noticed that there are 2 fuel pumps. When testing at idle I found only one pump is running. Pump 2 is not running as the relay 2 is not activated. This pump 2 relay is activated by a white wire which comes from the engine ECU. Does any one knows under what conditions pump 2 is activated ?

[Nik]

Has the fuel filter been replaced lately ?, I once had a Corvette Stingray that exhibited the exact same problems , filter changed , problem cured ,

Hope this helps ,

Nik

[Jonathan3004]

I have a very similar problem, mine had flat spots also and no engine light. But then was reporting lean fuel on one side of the engine, this then progressed to both sides. The main Jaguar dealer has had the car in three times and can't fix it, it has also been to two specialist neither can solve the issue. Mine is a 2002 4.2 XKR with 90k miles. I have replaced the plugs and coils last week, the car also had a new gearbox fitted 4k miles ago. It also had a new throttle body c5k miles ago. Now I start the car, drive a short distence, get restricted performance for 5-30mins it then goes away for the rest of the journey. If I stop the car and then atart it again it goes through the same pattern of restricted performance.

It is a complete nightmare!

The Jaguar dealer has had the car for the last two days and cant find the problem! They have checked the fuel pressure, fuel filter, injectors, change the MAF checked for air leaks everywhere and checked all the wiring and come up with nothing. They have emailed Jaguar for help and are awaiting a reply. I have to take the car back on Monday when their head machanic will have returned from holiday so he can have a look.

So any further suggestions are welcome but this is proving difficult!

Thanks

Jonathan

[Jonathan3004]

I pick up the car today and it seems to be fine!!!! At last,I hope this will be the end of the issues. They replaced the lambda sensors, the fuel filter and then a thermostat. I took it out for a drive today and it is running perfectly. Thanks to all for the suggestions. I hope only to be reporting good news from now on!

[jipo999jim]

I replaced the flow meter last week and now all accelaration is back .

[mike020150]

All's well that ends well! Mike.