Greetings! New to the forum and the F150 world. Just picked up this truck for my wife last weekend (couldn't pass on the price), and have a few things to sort out. The truck is a one owner, 2000 Super Cab 4X4, 5.4 auto, 200,000 mi.

The 5.4 idles very rough on cold startup, even if it's fairly warm out. The idle varies from 500 to 1,100 rpm. Light throttle produces just a hint of miss under no load (in park). Even after warmed up when parked, the rough lope is present. Actually sounds like a street/strip cam lope. SES light is on. The engine runs perfect after it has a few miles on it with no hint of miss or hesitation, and idles fine. Plenty of power and get up and go.

The Mrs took it to Autozone yesterday. They pulled codes, cleared them and the SES light turned off. She drove on the freeway after that and a bit through town on the way to the safety check place. The SES light stayed off during a couple of on/off scenarios and it passed inspection. A few miles after she left, the SES light came back on.

Here are the codes they pulled. The code reader provided the possible problem areas, so I have those. Seems to point to the MAF, or possibly a vacuum leak. I have a Powerstroke, so I'm used to sorting through these things and fixing them myself, but I could use a little baseline direction when it comes to this sweet little gas burner. Any help would be appreciated.

P1151
P0136
P0156
P1131
P0174

 

Likely a vacum leak on the back Of your intake manifold

 

Welcome....

There's a rubber 90* elbow on the back of the intake manifold that's rots out and causes a vacuum leak....

Also look in the how to section of this forum on cleaning the tb and iac....

Link>>>https://www.f150online.com/forums/articles-how-tos-119/

 

Thanks for the welcome and the link as well.

That elbow looks pretty hard to get to. Is this usually a stocked item at Autozone or Oreillys? This weekend I will remove the TB and IAC to clean. I should be able to see back there better.

I did notice today that the PCV hose to connection at the intake is cracked through and weeping oil, and the hose above it is loose at the intake connection as well.

 

They might be dealer only items...

 

The whole PCV hose assembly is a dealer item, I think it's in the $30 to $40 range. If it's just the elbow at the back of the manifold, I think you can get a Dorman that works on the HELP pegboard at a parts store.

Fix all vacuum leaks, put a new Motorcraft PCV valve in, clean the IAC, MAF, and throttle body, clear the codes again and go from there. At 200k, depending on maintenance history, you may need spark plugs, one or more coils, and/or front O2 sensors.