5.4l. went from 3&5misfire,to multi misfire,to low fuel p...

Q: 5.4l. went from 3&5misfire,to multi misfire,to low fuel prsr bnk 1to limp mode now.tried comp rest,still limp.have code reader me

asked by on September 20, 2017

Went from codes misfire cyl 3&5, to multiple misfire, to low fuel pressure bank 1 to flashing o/d light with code for a valve in transmission now and is in limp mode now. This all started with changing the spark plugs. I've checked c.o.p and injector connections. I see on the 4.2&4.6 that the plugs have diff suffix for diff cylinders but not on this 5.4. . Tried resetting comp and better fuel, new oil & filters, mass air sensor & throttle body been cleaned also

My car has 191742 miles.
My car has an automatic transmission.

If the problem started literally upon start up after installing new plugs I would first suspect a problem with the plugs, or something was damaged during the work or something is not properly connected. Of course, coincidences are possible, such as a failing fuel pump (you refer to a low fuel pressure indication), but I would just take it from the top and re-confirm all work done in replacing the plugs (including be sure you have factory OEM approved plugs), and test all connections that might have been disturbed in replacing the spark plugs. If the trouble does not come in to view, a mechanic will pinpoint it for you, regardless of the cause. To obtain that service, please simply request a misfiring diagnostic and the responding certified mechanic will get this diagnosed and resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic.

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