E32 driving me mad

[S35mln]

Ok ...before i pull the remainder of my hair out .I really need some sound advice ...ok my car is a 1994 740 with M60 engine which is also fitted with LPG
When i start the car is  runs rough and does not respond to the accelerator pedal it appears to be a fault with the DME 3.3 diagnostics to do with the Mass air flow sensor ...however i have replaced that along with the throttle potentimeter and the problem still persists ..however when upto temp and switched to LPG the throttle works fine and when switch back to petrol when upto Temp it works ok also ...the problem appear to be when the engine is cold 
Problem 2 is that when i switch just ignition and dont start the engine all my lights ..indicators etc work perfectly 
..however when i start the engine the power to the MAF is lost and also to the Throttle Position Sensor and the lights cannot be switched of even after keys have been removed ..I have checked for faulty light switch but they are all ok and the only way i can get the front lights to go out is by disconnecting the battety under the back passangers seat.....its driving me absolutely nuts so any help or advice would be great ...thanks in advance
When i clear the faults on computer everything is perfect all lights work fine but when switch engine on all hell breaks loose with the electrics ...some lights work and some dont ....please someone help me before I lose the rest of my hair
I thought it could be a ECU problem ..but a lovely guy who is very knowledgeable things it won't be the ECU because he says  if it was the car would not even start .could it be 80% of ECU is working and 20% is damaged or does it not work like that ???

[Greydog]

Hi I responded to your other post but here goes with this one 

First don't discount the ECU check all the pins in the ECU are clean and not corroded same applies to the ECU connector use a good quality electrical contact cleaner not something like WD40

The ECU is in communication with many other control units and if signals are not received it can cause all sorts of issues. So it is very possible for the ECU to still allow the engine to run (badly) even while not getting information from all the inputs it needs. Some of the issues you report point towards a failing LCM (lights staying on etc) To be sure you need a proper diagnostic session if you can't DIY there is a Register of BMW Specialists just Google it there should be one close by.

Dave