popping noise

[tilliepeople]

While driving my 2001 expedition the engine started a loud popping noise .
Almost sounds like I blew a spark plug out .
It's been showing codes P0171 and P0174 since the weather got cold .
and now added P0125 and P0307
Thinking I blew a gasket someplace but can not find it .
It's about 10 degrees and I am working outside .
I have an appointment at a shop tomorrow but would like to have a better idea as to what could cause this .
Oh yea , it is a 5.4 4x4

 

[docraymund]

You may need to check the coolant temp sensor and the spark plug and fuel injector on cylinder 7. You have a lean misfire.

 

[1955moose]

P0307 is misfire on #7, if you blew a head gasket, normally you'd have two banks side by side acting up. The p071 and 074 are real common, usually something involving pcv hose, or elbow. One member actually had those two codes and had a failing fuel pump. Hate to jump to conclusions but it sounds like a bad valve on #7 or an adjacent cylinder. The other thing that sometimes causes a popping is a failed smog pump. Keep us posted what you find, post it for the others, Moose.

Sent from my N9131 using Tapatalk

 

[tilliepeople]

Now I feel foolish.
Turns out I actually did blow a plug out.
mechanic said it was pretty normal for these engines .He was sick and going home so I drove back home .
Threads on the plug still look pretty good ,so tomorrow I will attempt to just put a new plug and coil in it .I might have to run out and buy a thread chaser but that is better than having to put a helicoil in
.

 

[Plati]

Is there any chance the problem that lead to the P0171 / P0174 contributed to plug blowout?

I just replaced a damaged PCV vacuum hose elbow to fix that on my 2003 5.4

I think I read somewhere that my 2003 5.4 is before the 3V problem and after the plug blowout problem. Clean living I guess.

 

[1955moose]

Those codes are #1and #4 lean codes. What cylinder did spark plug spit out? Your mechanic had to be on deaths door to miss an ejected spark plug,! You dodged a bullet if the threads are intact. I've never heard of a jettisoned spark plug that didn't take the threads with it. I wouldn't chance not putting a nut sert thread on that bank. The chances of the new spark plug holding are slim with out it. I know these early models are tough but 14-18 ft lbs on spark plugs usually keep them intact. Sorry you had a plug spit on you, but better than a burnt/broken exaust valve, or broken spring!

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[tilliepeople]

Although he looked like he was on deaths door he is not the one who missed it .I was.
Even though I knew what it sounded like it never occurred to me that it actually would happen Only time will tell if it contributed to the fault codes ,but it is very likely.
I do hope I dodged that bullet .This mechanic is just now setting up his business an told me he did not have the tools to put a helicoil in and recommended a different mechanic

 

[1955moose]

Shop around, find a mechanic or better still a machine shop that's successfully done the repair. Good luck, Moose.

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[tilliepeople]

I went ahead an re-tapped the threads. yes it will probably blow out but finances dictate at least trying it.Torqued good so I am a little optimistic
The mechanic did recommend another mechanic that has the equipment to do it right so it may go to him in the near future

 

[Plati]

Retap threads? Won't that dump the cuttings down into they cylinder?