X Type air leak

[Jonny P]

Morning all,

Having recently bought my X Type 2.5, it started showing (which I now realise are very common) symptoms of an air leak in the vacuum system somewhere. I have invested in a code reader which is showing both codes P0171 and P0174 which also points to this. Having replaced the two O rings on the sensors connected to the intake manifold and also changing the breather pipe between the air intakemanifold and the engine for the updated ribbed version, the problem persisted. 

Rather than carrying on replacing everything it could be, I decided to try to find out where the leak is. I've sprayed carb cleaner around all points where there could be a leak but there's been no increase in engine revs, as you'd expect. Next on the list of parts to replace is the brake boosterpipe/valve.

Having read about this problem in great detail all over the web, I have to say my problem differs in as much as the warning light and "cruise not available" warning only comes on at motorway speeds, usually as I hit 70mph (I do a 70 mile round trip most days) at which point I pull over, wait for the revs to drop to idle speed, the warning clears and the light goes off and I can then drive on with no problems or warning for the rest of the journey. The main check engine symbol stays lit.

It's this that's stopping me just replacing everything, surely if there's a leak it wouldn't "reset" just because I pull over and let the revs drop? Or would it? Any help would be greatly appreciated.

Thanks

Jon 

[david moore]

found this with the codes, P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205, P0206
Concern with fuel system too lean/rich.
Fuel injector(s). Fuel delivery fault.
REFER to: Fuel Charging and Controls - 2.5L NA V6 AJV6/3.0L NA V6 - AJ27, VIN Range: E96603->J28492 (303-04A Fuel Charging and Controls - 2.0L NA V6 AJV6/2.5L NA V6 - AJV6/3.0L NA V6 - AJ27, Diagnosis and Testing

[david moore]

P0171 Right-Hand bank combustion too lean
Engine misfire Air intake leak between MAF sensor and throttle Fuel injector restriction Fuel filter/system restriction Fuel pressure sensor failure (low fuel pressure) Low fuel pump output HO2S (1/1; 1/2) harness wiring condition fault Exhaust leak (before catalyst) engine control module (ECM) receiving incorrect signal from one or more of the following components; ECT sensor, MAF sensor, IAT sensor, IP sensor, EFT sensor, TP sensor
P0174 Left-hand bank combustion too lean
Engine misfire Air intake leak between MAF sensor and throttle Fuel injector restriction Fuel filter/system restriction Fuel pressure sensor failure (low fuel pressure) Low fuel pump output HO2S (2/1; 2/2) harness wiring condition fault Exhaust leak (before catalyst) ECM receiving incorrect signal from one or more of the following components; ECT sensor, MAF sensor, IAT sensor, IP sensor, EFT sensor, TP sensor
also  found this too, good luck.... dave

[thanat0s]

item 6 Jaguar X-Type 2004 3.0i 169kW AIR BOX INTAKE RESONATOR VACUUM CANISTER 1X439F764

Hi guys, after reading the above description of the problems encountered I thought I'd throw in my 2 pennies.

I was having the same issue with my 2001 3.0 petrol V6, my 3rd which I've owned for 7 years. After much searching around the engine bay for the source of the strange hissing sound I found the airbox intake resonator had split along the join between the top & bottom. It sits under the engine cover, behind the air filter box. £12.95 off ebay for a replacement, cleared the codes & 3 months of normal driving so far.

Hope this offers some help.

Graham.