P0171 and Misfires - 2006 Expedition

[akpedition]

Hi, I had a P0351 code and after replacing the coil on cylinder 1 it went away but the next day I got 4 other codes. P0171, P0300, P0302, P0304, attached are the codes from reader, one is before replacing the coil and the other one is current.

Where would I start troubleshooting? I don't know what maintenance was done prior, so don't know if the plugs were even changed. Mileage is at 230,000ish.

 

[Hamfisted]

Inspect all your vacuum tubing and hoses. A smoke test machine would come in handy for this. The lean condition could cause the misfires on that bank ( passenger side ). So try to fix that first. If you don't know the last time the plugs were changed, or the fuel filter changed, it's always good to get those out of the way. Don't be shocked if a coil or two is bad, it's common at that age.

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[akpedition]

Thanks for the relpy. I changed all the plugs and replaced the fuel filter - all the codes went away, idles smooth, got its power back, and doesn't run rough anymore. Hope it doesn't return.

 

[Esat]

In my 2004 ,I had a case like this and I found out my inlet was leaking from seals, I bought an original one and replace that big plastic inlet on top of the engine . Problem solved . It's a bit big job but there is no other way to solve it. While I get the injectors I replaced the o-rings on them and under it in the middle of V knock sensor replaced.