Good day all your cleaver People
I am from Sunny South Africa and i need your help please
I have a 1991 Nissan 1tonner 3.0lt V6 (VG30) Single cab bakkie
it started idling iritic I send it to a Mechanic which removed my immobilizer and alarm. And he replaced the Spark plugs
Getting the Pickup back it sound like it was running on 3 cylinders , black smoke and raw fuel coming out of the exhaust.
I took it to a another mechanic and he said there was wires of and that shorted out the injectors that they stayed open. He fixed that. On collection of the Pickup I noticed as soon as I go over a bump its back to running on 3 cylinders. T took it then to Steve’s Auto Clinic and they said its w wiring problem . My wife say the Pickup is running on Kangaroo Fuel as it is jumping and jerking If I take of the airflow censers wires there is none or hardly any Difference in the car.

Where do I start. How do I test what is the problem as this Pickup has about 20 000 wires

Any help and advice will be much appreciated