I have a 98 f150 with the 4.6. It has been running bad for about two month's. It would idle rough and have no power going up hills. So I changed the pvc valve egr pressure sensor. Ran OK for a few days then same thing but worst going up hills. I had to stop and pull off the two vacuum lines to the egr pressure sensor to make it up the hill. I re set the computer and changed the fuel filter. Two days ago I stopped at a stop sign my oil pressure dropped all the way down and came right back up so I stopped autozone got oil I opened the oil cap started adding it and half way through adding it the engine was really running rough and almost stalling. I closed the hood and limped back home with it sputtering and almost stalling. Got home removed the oil cap again the engine started to stall it's sucking air into the oil cap so I took the pvc out and that same thing sucking a huge amount of air through the pipe. Any ideas here I need this truck it's my only transport. Thank you

 

Before you reset the computer, did you check it for codes? Did you use a MOTORCRAFT PCV valve?

 

Yes it was bank one and bank 2 two lean. Yes I used motorcraft pcv valve

 

Now I'm scared to drive it it's really bad and I don't have a scanner

 

Check for vacuum leaks.

 

I sprayed all the vacuum lines with starting fluid no charge in rpms or idle so I don't think I have a leak

 

Now I noticed that there is a sucking noise under the drivers side dash plus the egr vacuum regulator is pushing or sucking air in on the top after the engine is shut off

 

Follow the PCV line to the back side of the intake, the elbow rots out and causes a major vacuum leak.

 

OK but if the pcv pipe was leaking it wouldn't have a ton of vacuum at the pvc when I remove the pcv valve there is a tin of vacuum to the point it stumbles and almost stalls the whole time the pcv valve or hose is disconnected I might be wrong just making sure