Having an issue with the engine stalling. *****Typo Engine is a 4.0 not a 4.2*****

The issue:

Engine runs smoothly and revs smoothly upwards, it idles but stalls immediately if reved or returning to idle (as shown in the two videos below), a slight rev attempt will also cause an immediate stall. Initially work (detailed below) was undertaken to resolve a persistant engine fail safe mode.and after the codes detailed below were corrected, the car subsequently passed an MOT and was for a short time driving perfectly. This problem began to emerge shortly after the work done and has been progressively getting worse, the car drove fine but soon this issue emerged and would occur only in gear and coming to traffic lights, but now it is occuring in park, it's parked at home and I cannot drive it on the street any longer.

More details

I bought the car with a full service history but in fail safe mode.The original engine codes which have been fixed were P1722 P1719 C1155 C1095 now the engine is no longer in fail safe mode which initially corrected the problem. Work that has been done includes, new battery, full engine service, timing chains and tensioners, investigation of engine peripherals (engine was replaced entirely in its previous history), gear box has been serviced, throttle body has been replaced twice, most of the sensors have been replaced and checked. Everything mechanical has been checked, the car has been looked at by an experienced Jaguar mechanic, according to them the problem is electrical but they are stumped, recently my mechanic's colleague (electrical specialist) unfortunately has not been available due to personal circumstances so I have no further updates. Car is currently at home and I cannot drive it at all due to the stalling issue. Engine coolant low is a novelty as well.

Please see the videos below, in one of them the car idles then stalls immediately with light rev applied, in the other it is revved more and stalls upon a slow return to idle.

Any help pointers would be greatly appreciated.

Jaguar XK8 4.0 1999 stalling issue. Here idle, slight rev and a immediate stall.


Jaguar XK8 4.0 1999 stalling issue. Here idle, rev and stall as the rev is reduced slowly to idle.

 

As I understand it................
You installed a 4.2 liter engine in a 4.0 liter car and now you cannot get the electronics to integrate?

The AJ33 engines are not compatible to AJ27 cars without major modification to the engine management or engine itself. (sensors and mechanical parts etc)

'Frankencars' can be a 'bear' to get running correctly.

I hope it gets sorted and good luck.

 

My apologies that was a typo, engine is in fact 4.0 not 4.2

 

Watch the fuel trims (hot engine, parked).

May well be an air leak...

 

Try disconnecting the MAF and leaving it disconnected and start the car. Try it 2 or 3 times and see if she'll run before giving up on a bad MAF sensor. Shot in the dark