A rough idle developed in June, 2015. I have went through every possible solution. The problem seems to worsen, especially when it rains. The vehicle is now beginning to stall at intersections. The only possible solution I can imagine is replacing or cleaning the fuel injectors. I did determine that I was receiving a fuel injector fault from ONE fuel injector while using live data but I was unable to recreate the error. The other possibility is low compression or a damaged valve. Vacuum tests don't show and type of problems with catalytic converters or leaky valves. The most frustrating part is that the computer modules in this Ford vehicle do not report any errors. Not even a misfire or a stalling engine has thrown a (DTC) check engine light. I am only repairing this vehicle as a favor for my roommate. I have tested the IAC, replaced the DPFE, spark plugs and wires, cleaned the MAF, replaced the intake manifold gaskets, checked injector resistance, changed PVC, fuel pressure is at 64psi stable, cleaned ground connectors and relay box terminals, checked overall engine/chassis/battery continuity, and the list goes on and on. My only other viable option is to have a backup engine or two on hand.