Good morning fellow p38 diyers

Recently I bought another p38 it needs some attention but it’s good driving base. Since I got it, the service engine soon light is on. I have drive it 2 times and couldn't really determine what was going on. At first I thought the gearbox was slipping but now I think it has something to do with the service engine soon light. If I cleanr the code with an obd scan, it comes back after 5 minutes as soon as I start driving. Situation discription:

• When I drive and the light is off there is nothing wrong.
• When the light is on continuously the power changes.
• When the light flashes it still drives but stutters when accelerating and it seems like the gearbox is slipping because it goes high in RPM but does not accelerate.

I have replaced the oil, filters and spark plugs. In addition, this one consumes considerably more than my other one. This let me think it might be the Mass airflow sensor might be bad. I’ve got the workshop manual but don’t know what to look for or where. So now I’m wondering if you guys have any idea of what might be the problem.

Range Rover p38 MY2000, 4.6L petrol.

I recently bought a P38 from 1998 whit some work all around. I have been trying to get the tailgate to work but no succes, that's why I'm here. The lock mecanism of the tailgate is working because i can manually open it. I have replaced the button and actuator in the tailgate. I also replaced the ECU in the RH front door. If i press the button on the tailgate the actuator gets 6.4 V. What do I do now?