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View Full Version : HELP! calling all ford tech's.... need some input


bigrig81
12-14-2010, 12:11 PM
So I have a 2003 f150 5.4 automatic and when I am cruising down the highway it starts to feel extremely rough when I am at low idle in what seems to be any gear but more in overdrive or 3rd gear. If i hit the gas and the rpm go up it's fine. it just seems to be at the lowest rpm before it would shift down or when it just shifts up into a gear.

my thoughts are maybe a tps, but i would assume that it would do that if i drove at that rpm at ANY time, so maybe it's not that.

EGR? I'm probably wrong, but I figured that would mostly show at idle

CTS? causing tranny to not shift right?

Please tell me it's not the torque converter haha

ANY help would be appreciated!

:D

bigrig81
12-14-2010, 04:22 PM
ok so I scoped the tps and it had no spikes and ranged from about 1V up to approx 5V ish..... soooo hmmmmm

any thoughts?

Mud Slinging Dumb Fawker
12-14-2010, 04:48 PM
any codes

Deathtrap
12-14-2010, 10:02 PM
We had that at my work with our 05 5.4, same symptoms, was actually missfiring under load, replaced 3 or 4 of the coils and all the plugs, good as new.

bigrig81
12-14-2010, 10:22 PM
that was the first thing I tried and the MIL even came on and went off a week ago, but there was no codes in the memory. even tried 2 different scantools haha

I noticed today that the it kind of feels like it's maybe not shifting down.... if the road is flat and it's chuggin at low rpm, it's fine, but as soon as it's under load, it starts to (what feels like) a bad bad misfire. you think it could be a torque converter lockout problem? seen anything like this come in to your shop?

any help would be appreciated AJ!

thanks loads

:D

bigrig81
12-14-2010, 10:26 PM
We had that at my work with our 05 5.4, same symptoms, was actually missfiring under load, replaced 3 or 4 of the coils and all the plugs, good as new.


hmmmmmm i think that could be it too.. was thinking it felt electrical more than anything.... and i have had a leaking shraeder valve on the fuel rail i just found today... looks like it has been dripping off the rail onto a couple of the coils.

hmmmmmmm

:dontknow:

toyon35s
12-14-2010, 10:49 PM
sounds like it needs a tune up ,but it would run funny if the injectors are not getting proper pressure ,so fix you leak and see how it runs [cheers]

tchevy
12-14-2010, 11:00 PM
fiz the leak. you need plugs and boots, maybe a couple coils.

Mud Slinging Dumb Fawker
12-14-2010, 11:01 PM
hmmmmmm i think that could be it too.. was thinking it felt electrical more than anything.... and i have had a leaking shraeder valve on the fuel rail i just found today... looks like it has been dripping off the rail onto a couple of the coils.

hmmmmmmm

:dontknow:


fix that first and make sure there is no fuel down any of the plug holes aand check the plug boots for cracks

D-Ass
12-14-2010, 11:02 PM
Put a chevy motor in it then sell the whole thong and buy a dodge

bigrig81
12-15-2010, 08:57 AM
fixed the leak yesterday... it was minimal... will take a look at the plugs and coils and such when i get a chance tomorrow hopefully.

:D

thx!

bigrig81
12-16-2010, 09:28 PM
k so it seems to be all fixed.

tried getting technical and using the Snap-on modis that i have access to but couldn't find the misfire information. if anyone has one of those i have some questions for ya haha

ended up just doing it the old fashioned way ....(fuel leak had nothing to do with the misfire btw) ..... bought plugs and 4 coils. chnaged the plugs and coils on ones side... no fixxy .... took the 4 coils that I then knew were good and put them on the other bank with new plugs and it's all good :D

now to change the removed coils in one at a time to find out which one was the issue.

thanks for the help guys and to deathtrap for getting me on the right track!

[cheers]

pumpkin
12-17-2010, 07:35 AM
What do you need to know about the modis?

bigrig81
12-17-2010, 12:39 PM
What do you need to know about the modis?

I am just wondering how to find the misfire information. I found my way into the Global OBDII section then the Non-Continuous Monitors, but once I am in there the TID's available are only displaying the O2 sensors and such, but no misfire information. So I manually entered the TID, but once i was in TID$53 all i could see was it was showing a couple of cylinders and not all 8 CID's.

now that I think of it... would pretty much need someone to walk me through it with my machine. but if you have any thoughts, maybe i missed something :D

[cheers]

pumpkin
12-17-2010, 02:06 PM
Going through the tids is a pain in the ass. The two latest updates for the modis can do the missfire through identified vehicle rather than global. What version do you have? The 10.4 has a lot of ford stuff in it.

bigrig81
12-17-2010, 04:01 PM
hmmm that's interesting I should take a look. I am totally green at using it other than to get codes i will admit, i was shown and have a little booklet on using it through the TIDs to get misfire info so i was playing around with it when myt f150 started to miss. I should maybe look at getting updates... mine is from 2007.. i think it might be 7.2 version.

it's this pot of gold of information for diagnosis and i am itching to learn more about it haha

do you use it a lot at you shop?