I'm at my Wits end and don't know what els to do! I've got a 2004 5.4 The issue is something that I've been trying to fix for a couple months now. When the engine warms up it idles really rough and sometimes dies. When it dies the instrument gauge says Low Oil Pressure. I started by doing all the basics. New fuel filter, cleaned the MAF sensor. Don't know what els to do so I take it to ford. They put it on the computer and it spits out codes P0340 P0303 P0304 P0012 P0345 and P0174. Well after getting these codes the mechanic told me that he thought an oil change with a Ford Oil filter would fix this! lol well it was obvious to me that having them do any more work to it would be a waste of time. So I start doing research on this forum and find a post about the VCT solenoid. Well this sounded like my problem so I ordered a solenoid from Ford and replaced the one on the drivers side with no results. So after driving it for a day I put the old one back in and put the new one on the passengers side, start it up and now it wont idle right. It idles so low it wont stay running. Its almost like a separate issue. I did take and spray out the connector on top of the solenoid with MAF cleaner. could this have done something? ANY help here would be appreciated. I'm not much of a mechanic and this issue is giving me an ulcer!

 

Oh and one more thing. When its idling low or rough the engine is ticking really bad, but when you give it gas it comes alive... also when towing a trailer. a small one at that, I've noticed it doesn't have much power and I get about 6 MPG!!!

 

Read this write up I put on the subject. it may not be your issue but it should help you figure it out.
https://www.ford-trucks.com/forums/1...l#post10391541

Your mechanic is right about the oil change to a certain extent if it is timing related. The oil pressure when engine is HOT at the sending unit can not be lower than 25 psi. Also check your fuel pressure, it should be about 60 psi at the rail. If you have not changed your fuel filter in a long *** time, then replace it. When you take your old filter off, try to blow through it in the flow direction. there should be no resistance. Good luck