01 x 4.0 stumbling

[2009KVFD976]

I have an 01 x with a 4.0 and recently changed plugs and wires (motorcraft sp432) gapped at .054 and it stumbles and hesitates while accelerating to get up to hiway speed. the plugs i pulled out were motorcrafts too but gap was .030 already dumped lucas fuel sys cleaner and changed fuel filter too. air filter is clean as well. no codes except for p0401 after replacing egr valve, dpfe sensor, egr vac solenoid and it remains lit. only had p0302 come up once but it cleared itself up. maybe bad o2, maf, cat, fuel pump, fuel regulator, fuel filter??? Btw this thing gets around 220 miles per tank too. i used to get about 350-380...

 

[Lefty2053]

I have an 01 x with a 4.0 and recently changed plugs and wires (motorcraft sp432) gapped at .054 and it stumbles and hesitates while accelerating to get up to hiway speed. the plugs i pulled out were motorcrafts too but gap was .030 already dumped lucas fuel sys cleaner and changed fuel filter too. air filter is clean as well. no codes except for p0401 after replacing egr valve, dpfe sensor, egr vac solenoid and it remains lit. only had p0302 come up once but it cleared itself up. maybe bad o2, maf, cat, fuel pump, fuel regulator, fuel filter??? Btw this thing gets around 220 miles per tank too. i used to get about 350-380...

Why would you put a plug in gapped different in the first place? The gap is by engine not plugs used. At least this is what I have always done. No matter what plug I use I always use the engine required gap.

 

[2009KVFD976]

I think i may have put them in without gapping them since others have told me not to insert a gapper tool in platinum, iridium, nickel or other material besides copper bc it destroys the fine wire. but i found the problem,it was the #2 plug that the porcelain was cracked. luckily i had more layin around so i can put in its place. now it runs like a clock!!! As far as fuel trims go, what am i looking for?