May 02, 2008 · when cycling the key the pressure should read 38lbs. running pressure is 35lbs. are you having starting issues? With the engine running you can have anywhere from 28 to 50 PSI. With the key on... 2005 Ford F150 stalls at idle and surges Recently we came across a 2005 Ford F150 with a 5.4 liter engine that was stalling at idle and had a surging condition at lower engine rpms. First thought was to pop the hood and look and listen for vacuum leaks which we did as this would be the most common cause of this idle and surging condition. The 2006 Ford F-150 has 9 problems reported for cam phasers and lack of oil pressure during hot idle. Average repair cost is $3,090 at 88,500 miles. Ford recommends sae 5w-20 fully synthetic oil for the 2016 ford f-150. the truck's oil capacity varies by engine: the 3.5l v6 engine holds 6 quarts of oil and the 5.0l v8 hold 8 quarts. 70 psi at cold start 20 psi hot idle 58 psi hot fast idle 2000rpm. so i have today spoke to ford america who say replace the Oil pump with 5.4 mustang high output oil pump. can anyone shed some light on this oil pressure issue, as i have another four vehicle with similar mileage and don’t want to have to replace all the engines. Ford's 335 Series engines use a bit different oiling system than most other engines, and consequently many have low oil pressure - especially at idle. In fact, both Rusty, after its rebuild, and Dad's engine, before its rebuild, had a hot-idle oil pressure of about 10 psi. Fortunately, Cleveland engine guru Tim Meyers has a solution for that.