Still have a miss

[Sully]

04 F150 w/ 5.4L V8 w/ approximately 60K on the odo.

 

A few months ago, it developed a bad miss. I checked the plugs (new in December), new fuel filter in December, checked/cleaned the air filter, pulled the MAS and cleaned it, pulled the throttle body and cleaned it. It seemed to be running fine after that.

 

Lately, it's been missing a little bit again. At idle I notice the miss every so often at random. I could be sitting at a stop light and feel the miss once. Sometimes I don't feel the miss sitting at a stop light. It's very random.

 

I also noticed lately that while I'm cruising the highway at 65 - 70 and slightly ease off the accelerator, the truck bucks pretty bad. It's not throwing any codes.

 

What else can I check that could be causing this? I'm really stumped. I don't want to take it to a stealership to have them put it on a machine, say they find nothing wrong, and charge me a butt load. I feel that it's got to be something simple that I'm overlooking because I'm overthinking this.

 

Any ideas?

[Dave1647545494]

it probably has a coil or a boot going bad, but you'll have to wait for it to throw a misfire code before you know wich one

[Sully]

but you'll have to wait for it to throw a misfire code before you know wich one

 

That's what I'm afraid of. This problem is getting really annoying and I don't know how long I'm going to have to wait before it throws a code, if it ever does.

 

I've been doing some research. Do you think it could be the TPS?

[Guest tbutera2112]

on that engine...most likely a plug or coil

 

ide advise changing the plugs...but its a major bitch to do, and very expensive if you pay someone

 

also, if you change them they NEED to be torqued to spec, no hand tight plus a quarter turn BS like most engines

 

i think the 04 has the updated heads, i know on the 4.6 cars they did and since they use the same heads on the 4.6 and 5.4, ide imagine so....so i wouldnt worry too much about plug blowout etc

 

 

try changing the plugs and go from there

 

and if it annoys you too bad, take it to a dealership and they will tell you which cylinder is missing...they can put it on the diagnostic program and drive it and it will monitor the cylinders...doesnt have to throw a code for them to find it

 

these things throw codes sometimes, other times not...i wouldnt hold your breath...my mod motor blew a spark plug completely out, destroying a coil as it went...didnt throw a code, but i had some oil from a leaky valve cover get in one of the plug wells and threw a code....the mod motors are weird like that

 

i did plugs on mine and ended up having schmuck come help me get the two in the back because i lack the skills

[Sully]

Rob put new plugs in the truck in December and I checked them all again a few months ago when this started.

 

I'm beginning to think it's a COP or TPS.

 

I might just end up taking to Ricart next week and have them check it out. Ugh. I soooooo don't want to do that though.

[Guest tbutera2112]

i understand you live in canal so ricart is most convenient...but i will NEVER let them touch anything i own ever again...fuck them

 

 

 

and it could be a TPS, but ive never personally seen those being problematic on the mod motors, especially with so low miles

 

havent really seen the COPs go bad that often either (on 04 cars/truck atleast)....if you do have a bad COP then only replace it with an OEM one...aftermarket are all junk, even the performance ones (aside from the weapon x)

 

oem cop is like $125 from ford (when i bought mine they were...its been awhile though)

 

if you can diagnose it as a COP for sure though, i would look into buying a set of weapon x cops... theyre a completely different design and theyre proven to be much more efficient

 

http://www.rpmoutlet.com/musv8wgf.htm

 

 

 

after doing headgaskets on my 2v, the guy who did it put the cops in and one of the prongs got bent causing a nasty misfire...it didnt throw a code for a bad COP, but the dealer found it right away and fixed it no charge (i paid for the diagnostic, $79, but not any labor on them fixing my cop)....that was krieger

[Sully]

Yeah, Ricart is pretty much within walking distance from my house, but I am not fond of them either. I've had awesome service from Jim Keim Ford. After reading a bunch of stuff, I'm thinking that it may be in my best interest to take it there and let them run diagnostics on it. I could spend hundreds replacing parts and never fix the problem. At least with their diagnostics, they hopefully can tell me what the hell is causing this. If they could at least do that much, I would then have the option of buying the part and replacing it myself or just let them do it, depending on cost.

 

FFFFUUUUUUUUUUU.... I think that's what I'll do next week.

[Crossle]

What you really need to do instead of throwing parts at it is diagnose the problem. You need to hook up a scan tool and take a look at the fuel trims. I think you will find a lead there, if I had to "guess" based on what you have replaced I think you will find a vacuum issue either the PCV system, intake manifold, etc...

 

Good luck!

[Sully]

I have an appointment with Jim Keim Ford Wednesday morning to see if they can diagnose the problem. Besides, my front SRS impact sensor is bad as well, so I'm going to have them replace that while I'm there.

[2 Sweet]

Almost sounds like the IAC could be causing the problem, but I don't think that would cause the bucking at freeway speeds, would it? Maybe the EGR then

[Guest tbutera2112]

Almost sounds like the IAC could be causing the problem, but I don't think that would cause the bucking at freeway speeds, would it? Maybe the EGR then

 

IAC would affect the car at idle, nothing else...wouldnt hurt it at freeway speed unless he put it into neutral or put in the clutch if it was a stick car

[Sully]

Diagnostics said that the coil packs on cylinders 3 and 7 were bad. They wanted to charge me 2 hours of labor to put them in. BWAHAHA!! I went to the parts department to get the coil packs. $130 for 2. I talked to the parts guy a bit then called Brady. He couldn't get them for any less because they are OEM parts. I talked to the parts guy some more (just bs'ing about cars and stuff) and he sold them to me for $103 out the door. I went home, installed the coil packs in less than 20 minutes. I drove the truck to work and I still have the same problems.

 

So, I'm wondering if it's going to take a few cycles of driving for the PCM to relearn how to manage the air/fuel now that I replaced the bad coil packs. Is that possible? I don't know. If replacing the 2 coil packs doesn't fix the problem, what in the hell could it be???

[Guest tbutera2112]

diagnostics said the miss was on 3 and 7, or specifically said those COPS were bad?

 

have you checked the plugs on 3 and 7?

 

are you sure you changed the right packs?

 

rear bumper

4 8

3 7

2 6

1 5

front bumper

 

thats the cylinder pattern you should be following for the mod motors

 

 

the PCM shouldnt need to relearn...when my intake was cracked it was dumping coolant down plug well 5 and making it miss...ide pull over, dry the coolant up, and it would run fine

 

if youre sure you changed the right COPs, then i would take the truck back to the dealership and ask to see the service manager...tell them you paid them to diagnose it, and they did and the problem is still there, and ask them to rediagnose it for free since the problem was not where they said it was, or was a separate issue altogether

 

also, on the COPs you installed, make sure you installed them right...theres prongs you need to watch for bending, and make sure the springs are seated properly

[Sully]

Yes, they said the COPS were bad on 3 & 7.

Yes, I replaced the correct ones.

I was very careful when plugging the connector back onto the COPS.

I'm not quite sure how I would make sure the springs are seated properly since there's absolutely no access to the boot once the pack is in place. I just press down on the COPS and wiggle it around to make sure it's seated.

[Guest tbutera2112]

i would take it back and ask them to rediagnose it on their dime since their original guess appears to be wrong... if they say no, ask to speak to the service manager...usually the service managers dont wanna deal with the hassle so they agree

[Sully]

They also told me that when the coil packs are replaced, they need to reprogram the PCM. When I talked to Brady, he said that it is not needed. They probably just want to update the code, which has nothing to do with the COPS or this issue.

[Guest tbutera2112]

nope nothing needed with the PCM... ive blow coil packs before and not had an issue...i blew a plug out and it took the coil with it and didnt have to reset anything

 

 

maybe as a last resort, disconnect the battery for a little bit and then reconnect it and drive it...but i really dont see that working, guess its worth a shot...

 

without being able to diagnose the cylinder, theres not much more you can do...best bet is to talk to them and see what they say about re-diagnosing it

[Sully]

I unhooked the battery and let it sit like that overnight. Still has the issue. I called the service department this morning. They said I can bring it back in for another diagnostic and they won't charge me. I'm going back Monday morning. This sucks.

[Sully]

The plugs in 3 & 7 were bad (cracked). Also the terminal nut on both of those plugs backed off a bit from engine vibration, which caused them to spark and possibly ruin the COPS. They suggested that I leave the new COPS installed and not put my originals back in.

 

The service writer initially told me today that they would charge me for 2 new plugs and not charge me any labor. Total of $40. I was cool with that. The service tech and I went for a test drive after he was done. Truck runs great. We get back to the dealership and the service writer hands me a bill for $18.78. Sweet! They hooked me up today.