air pump don't use the std one, replace it with a good after market pump and the system should be fine
This is probably the best tip IMO.... If I were to find myself in a P38, that would be first on the list - possibly an Endless air setup. If you can get a decent size compressor that fills the 10 litre tank quickly, it won't matter if the bags are leaking a little bit.
What tends to happen is one or more bags start leaking first. Then overnight one bag loses all its air, and the EAS self levels a couple of times throughout the night, thus removing air from all the other bags. The pump is so small and slow (even when brand new, they take about 5 mins to pressurise the tank to 10bar (approx 150psi)), that it can't supply enough air to bring the car to target height before the computer logs a code. Especially if the pump is old, they thermal cut regularly under this long runtime condition (pump gets too hot and the system shuts it down for a while).
If you can install a maxair/arb or similar compressor on the side of the chassis and wire it into the standard pump wiring, you'll find the EAS works MUCH faster from lowest to highest setting. You could also just install it with a separate switch on the dash and just tee it in to the reservoir line - just make sure its wired through a 150PSI pressure switch.
If you hook a P38 up to workshop air (150psi with an industrial size reservoir), they will go bottom to top in about 3 seconds.
84 Rangie, 3 inch spring lift, 2 inch body, Megasquirted 4.6, R380, rear Maxi, 34x11.5 JT2s. Simex FM installed.