Hello, new here and to the fox body mustang. This may get a little long but looking for some direction. Searched the form and could not find what I am looking for. Picked up a 91 5.0 Lx auto about 3 months ago for a birthday gift to my daughter. Car sat in storage for a few years. Over the last few months me and my dad have fixing what looks like most of the normal problems these cars in counter with age. This car has always started, ran, and drove. Due to this car sitting so long we did the normal change of all fluids and filters, new plugs ,wire, cap, and rotor. Adjusted tps, and cleaned maf. This car started and ran fine after all this work, that was done about 2 weeks ago. Fast forward to this week. I am on vacation and I get a call that the car won’t start. Dad troubleshoots and believes the fuel pump has failed, car has spark and will fire on carb cleaner. Being older and me 1000miles away the car is sent to a shop to have pump changed, with no joy. They also threw a TFI in it with no change. I asked him to get the car out of the shop due to them guessing and not troubleshooting it. I returned from vacation last night and had a little time to look at car. Here is what we know, key on, fuel pressure goes to 20psi, I here clicking in L/s kick panel and fuel pressure goes to 38-40 psi on gauge connect to Schrader valve. I can not here this pump come on, old pump I could here come on and shut off in about 5 seconds. Injectors have battery voltage at red injector wire. Did not have node light to check pulse(will be getting today). Tried to check for pulse wit a test light with no blinking. If this is right I would believe the pip is faulty. Her is what is throwing me off. When I go to dump the codes, the CEL light becomes very dull in the dash and I have the clicking in the L/s kick panel. If I go by the clicking I have code 12,13,22,&23, idk if this is accurate. Cel is bright with key on and in park, it becomes dull when put in neutral , is this normal? Bad ground? I will be checking today. Sorry for the long post, just looking for anything we have not thought of.