Hello team, I have this strange situation, where my car is moded with the following: - Ford Aluminator 9.5 (low compression engine for boosted applications) - Procharger D1SC - Lethal Performance Dual Pump Fuel System (return style) Recently, noticed that under Boost, 1st, 2nd, 3rd Gears wit WOT, fuel pressure is perfect, then in 4th gear, fuel pressure drops from 60psi to 15psi (making car goes very LEAN)..!! So, I investigated the Fuel Pumps, and found one of them leaks a little bit, so I changed it, ended up with 2x WALBRO Pumps (1x 400lph, and 1x 450lph). Now, made the test again, with the same result, perfect FUEL PRESSURE in 1/2/3 gears, and in 4th drops again and goes lean. Any advices? what to check? - Is it something might caused by ( weak battery - Voltage )? if yes, how can Identify this? - Is it something related to the Fuel Controller (that piece in the trunk behind the back lights) might be faulty and not able to send the correct signal to the pump?