Gee 3 hours getting to where i.can post
ok I have a 2006 5.4 f150 ..started missing and got worse till.i had to do something
I have replaced 8 plugs 8 coils still missing no power codes are still.on the same cylinders
4-5-6-8 sometimes 7 ... idles rough the truck won't go over 40
Any ideas the fuel injectors are good ???? Maybe fuel filter ??

 

Could be the fuel filter,, but you wouldnt get a miss on one cylinder. As far as 7 try switching the coils,,,, even if they are new. Check the trans too??? Bad running engine wont keep it from going over 40. Could be the VSS,,,,i think thats it,, basicly timing problem.

good luck

 

Any codes?

 

Please post the exact codes.

 

The only codes are p0304-p0305-p0307-p0308 which are misfires detected
Same codes as before new plugs,coils

 

Same cylinders before and after the plug and coil change? I think I might do a compression test.

 

Thanks guys #8 coil bad catalytic converter drivers side fouled
Runs great full power no misses
You guys are great thank you ever so much
JAN

 

That doesn't explain the miss on #4 though.