i have a 2000 f150 5.4 on startup i was getting a stumbling of the engine, so i replaced the plugs coil packe, iac valve crank and cam sensor and maf senor. reset computer . idled fine let idle for 10 mine then took for short drive for computer to learn the new parts, no problems, went home shut off restarted then the stumbling started again the coil packs weer failing on both sides, so i shut off ignition turned right back on the stumbling quit like there was nothing wrong, i can go all day where it works great , then i can shut off veh come back later start up it will stumble then as i said turn off ignition then torn on immediately then it goes away, sometimes it takes two or three time for it to go away, i also changed the ignition key switch and the plastick ingnition switch box on steering colum.when it errors out one or two circut malfunctions on both banks for the coil paks, ,,,,1, could the pcm be going bad or could there be a malfunction at that wireing block where they connect together on the fire wall passagneger side , then on one side it goes to pcm the block is just located below the starting relay . i think i described it right.. the codes i was getting were po352.po354.po355,po357 and po174,po171, as i said i turn switch immediatly off then back on and the the engine runs fine, clear codes, later on when i restart the same thing happens , check engine light comes on same codes , if i didnt shut engine off it would run fine all day,

 

Double check your coil & injector connections on cylinders 4,5 and 7, also look for vacuum leaks,

Clear the codes and see which come back.

 

i did rest codes started up works fine , but sometimes when i shut it off and come back to it later to start it will stumble and code out circut malfunction on both sides, so i turn switch on and off a few times then it will run just fine, and like i said before there are times i can start it with no probles , iam stumped!!!!!!!!!!!

 

what codes keep reoccurring?

some times the spades/pins get bent or pushed back within connector to the coil or injector....thereby, not keeping consistent connection.

it might not hurt to check the connection or check the crankshaft sensor too.

have the vacuum lines been thoroughly checked for leaks??

 

Of the codes listed, two are bank 1 and two are bank 2.
You have an electrical intermittent.
All coils and injectors are fed from the same fused source.
It may be the harness plug going back to the computer.
.
The 171/174 codes are a separate and different issue.
Usually a common vacuum leak affecting all cylinders as excessive air making for a Lean condition the Ox sensors detect. This causes the fuel tables to go rich for both banks setting the codes. This will also cause rough hot idle and possible stalling.
Good luck.

 

Yes, check the connections, including the computer.

You can check for vacuum leaks by using an UNLIT propane torch.