02 f-150 misfire only under load
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Joined: Aug 2006
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From: Toronto, Ontario
02 f-150 misfire only under load
hey everyone, i havent posted here much as i have a focus lol but my dads got an 02 F-150. its got a 4.6L v8 and its totally stock except for the K&N drop-in. 81,000kms.
heres the problem.
it started with just an EGR code (P0401) how it wasnt flowing right, but i think its just sticking. now its P0303 which is cylinder 3 misfire detected along with P0316..which is misfire dected in first 1000 revolutions, cylinder not specified.
it has a coil-on plug system, i switched coil 1 and 3 and plugs as well (plugs look fine), its still throwing cyl 3 misfire. so im pretty sure its not the coil going bad, it ONLY does it when its underload, if i just touch the gas slowly it'll shake like crazy. if i nail it and go WOT its fine.
is it the injector? i don't feel like going to ford for a 100$ scan
heres the problem.
it started with just an EGR code (P0401) how it wasnt flowing right, but i think its just sticking. now its P0303 which is cylinder 3 misfire detected along with P0316..which is misfire dected in first 1000 revolutions, cylinder not specified.
it has a coil-on plug system, i switched coil 1 and 3 and plugs as well (plugs look fine), its still throwing cyl 3 misfire. so im pretty sure its not the coil going bad, it ONLY does it when its underload, if i just touch the gas slowly it'll shake like crazy. if i nail it and go WOT its fine.
is it the injector? i don't feel like going to ford for a 100$ scan
Technical Article Contributor
Joined: Oct 2005
Posts: 25,641
Likes: 19
From: MI
hey everyone, i havent posted here much as i have a focus lol but my dads got an 02 F-150. its got a 4.6L v8 and its totally stock except for the K&N drop-in. 81,000kms.
heres the problem.
it started with just an EGR code (P0401) how it wasnt flowing right, but i think its just sticking. now its P0303 which is cylinder 3 misfire detected along with P0316..which is misfire dected in first 1000 revolutions, cylinder not specified.
it has a coil-on plug system, i switched coil 1 and 3 and plugs as well (plugs look fine), its still throwing cyl 3 misfire. so im pretty sure its not the coil going bad, it ONLY does it when its underload, if i just touch the gas slowly it'll shake like crazy. if i nail it and go WOT its fine.
is it the injector? i don't feel like going to ford for a 100$ scan
heres the problem.
it started with just an EGR code (P0401) how it wasnt flowing right, but i think its just sticking. now its P0303 which is cylinder 3 misfire detected along with P0316..which is misfire dected in first 1000 revolutions, cylinder not specified.
it has a coil-on plug system, i switched coil 1 and 3 and plugs as well (plugs look fine), its still throwing cyl 3 misfire. so im pretty sure its not the coil going bad, it ONLY does it when its underload, if i just touch the gas slowly it'll shake like crazy. if i nail it and go WOT its fine.
is it the injector? i don't feel like going to ford for a 100$ scan
You can replace all the coils on the motor for $75 yourself -
http://cgi.ebay.com/ebaymotors/NEW-I...mZ180262041059
You can try swapping an injector. It sounds like weak coils - even though you did swap them. You can change the fuel filter and then check fuel pressure to make sure everything is fine there. Make sure the wiring harness isn't to close to the AC accumulator, that can create havoc on the ignition system and it might be picking on #3.
Last edited by jbrew; Jul 7, 2008 at 07:29 PM.