2003 5.4 triton misfire at idle
08-12-2017, 01:31 PM
#1
Junior Member
Thread Starter
Join Date: Jul 2013
Location: Thunder Bay
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
2003 5.4 triton misfire at idle
my kid blew his 2003 F150 5.4 Triton to pieces (literally 5 out of 8 cyl). i replaced it with a 99 5.4 which i used as a core (ran mint) i swapped all the sensors, harness, intake, fuel rail, etc. & put in new NGK plugs while engines were out and on stand,, but now that its back together it has a rough idle, runs fine when your on the gas though. my scanner says "lack of HO2S12 & Too lean bank 2". into shop where they said misfire on cyl 1/7/6/4, so 4 new coil packs there... still rough... any ideas ?? been checking all the connections, look good. unplugged MAF and Int air temp sensor from intake and it instantly ran slightly better.. I thought that because of the damage maybe the downstream O2 senors got coated with oil...
08-12-2017, 02:04 PM
#2
My dad has a 2005 5.4, as you know they are notorious for the fuel injector and spark plug fiascos.
Since you swapped out all plugs and coils, have you checked the fuel injectors? I would also swap out the O2 sensors like you said. Also maybe clean the MAF with electrical contact cleaner. Also, new air filter.
Since you swapped out all plugs and coils, have you checked the fuel injectors? I would also swap out the O2 sensors like you said. Also maybe clean the MAF with electrical contact cleaner. Also, new air filter.
08-13-2017, 07:29 AM
#3
Junior Member
Thread Starter
Join Date: Jul 2013
Location: Thunder Bay
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
I cleaned both MAF and the one inside filter housing,, unplugged O2 sensors downstream of cats, no difference. I UNPLUGGED the MAF and sensor in filter body and it idles perfect....
