There was a fuel pressure gauge put on the fuel distributer to check fuel pressure. Seems I have a fuel relay going bad. But we notice that the fuel pressure would suddenly drop once it drifted down to about 30psi. We turned off the engine and it held pressure for a while while it slowly drifted down. Once it hit 30 psi, it suddenly dropped. What's the cause? Bad o-ring in fuel distributor, bad accumulator or bad check valve at fuel pump? Or something else?