'04 Expy 5.4 - p0306 not resolved by changing plug. Truck shaking.

[Fat Slob]

Truck started shaking/stumbling especially at idol. It has reduced power and is hesitating. Pulled code p0306 and changed the plug which was terribly crudded up... (this is a new engine with about 50k miles on it). I thought it did the trick but after just a minute or two the shaking returned. The p0306 code returned as well after being cleared after plug was changed. I'm getting no other codes but that one.

I've read about this issue and seems people have change plugs, injectors, etc and still having issue.


Any suggestions of what I should try here?

Your help is appreciated.

 

[deweysmith]

Did you check any of the other plugs? Only one was kludged enough to throw a code but I would bet the others are pretty crummy looking too.

How long did you drive it with the crummy idle? If it's not throwing any more codes I would disconnect the battery for 10-15 minutes and then reconnect it and do the idle re-learn procedure in your manual. It's possible it acclimated to the bad plug and was compensating with the computer.

I'd still check/change all the other plugs first.

 

[Fat Slob]

Did you check any of the other plugs? Only one was kludged enough to throw a code but I would bet the others are pretty crummy looking too.

How long did you drive it with the crummy idle? If it's not throwing any more codes I would disconnect the battery for 10-15 minutes and then reconnect it and do the idle re-learn procedure in your manual. It's possible it acclimated to the bad plug and was compensating with the computer.

I'd still check/change all the other plugs first.

Drove it a couple days with crummy idle. Then changed plug 6 and made one trip this morning. We have changed a couple of the other plugs within last month or two when code would appear for those. I find it odd that a new engine with only 40-50k miles is getting that much crud in the plugs although I'm a rookie youtube mechanic so I really have no idea.

I will definitely try the battery disconnect and see what happens.

 

[deweysmith]

Definitely bizarre that plugs are dying that early, but I don't know how frequently they are recommended to be changed on the older Expys. I drove a 2000 F-150 a while back and that recommended new plugs at 100k so I bet yours is similar.

Are the plugs you're taking out oily or ashy? Broken insulators?

 

[Adieu]

Truck started shaking/stumbling especially at idol. It has reduced power and is hesitating. Pulled code p0306 and changed the plug which was terribly crudded up... (this is a new engine with about 50k miles on it). I thought it did the trick but after just a minute or two the shaking returned. The p0306 code returned as well after being cleared after plug was changed. I'm getting no other codes but that one.

I've read about this issue and seems people have change plugs, injectors, etc and still having issue.


Any suggestions of what I should try here?

Your help is appreciated.

Coil or injector.

Had to change out that trinity to get rid of my shake in idle & p020# + p030# for a misfiring cylinder on the 5.4

Oh and make sure there isnt coolant seeping onto the coil pack

 

[Fat Slob]

Are the plugs you're taking out oily or ashy? Broken insulators?

Oily, very oily.

Also, I disconnected batt cable and let computer reset but that didnt make any difference. Truck still shaking especially at idle while in gear. It shakes much less in neutral but still shakes a bit.

 

[Fat Slob]

Coil or injector.

The coil was dirty but wasnt worn or cracked or anything like that.

How hard is it to change a fuel injector? And how do I know which one to change, is it right in line with that cylinder?

 

[Adieu]

The coil was dirty but wasnt worn or cracked or anything like that.

How hard is it to change a fuel injector? And how do I know which one to change, is it right in line with that cylinder?

Super easy. Just like changing a coil (except it drips a tablespoon or so of fuel out when you unclip it).

Unplug injector. Release one or two bolts on the fuel rail I forget, pull up the rail so the injector clears the engine block, unsnap the injector from clip while holding a paper towel around it. Clip new one in, reseat fuel rail, screw it back in and plug it all back in.

0306 references #6. Injectors cost 30 to 50 bucks a piece shipped, older motors might also have mildly suspicious Chinese options with all 8 injectors for the price of 2.

PS its suggested you put a little motor oil on the injector gasket before putting it in

 

[Adieu]

PPS first check that #6 is plugged in properly and clean the connector. You can also measure the impedance between the pins on the connection and compare it to the two next to it to see if it's jacked up (although if its just clogged it might measure the same?)....however, if the impedance is different from the other onrs, it is DEFINITELY the injector that needs changing

Oh yeah and check that the plug is seated correctly on #6 and that do the same measuring thing across the pins with the coil.... cuz technically the code for an obvious injector #6 circuit problem is p0206, on mine it WAS p020# and p030# at first, swapped plug and coil p030# went away p020# and the shakes stayed. Swapped the injector, p020# and the shakes went away as well.

 

[deweysmith]

Oily plugs are bad. I doubt it's an injector, oily plugs themselves can block spark and cause your misfire.

If you want to check/replace the injector, that's definitely easier than fixing your oily plugs, but I'd be very surprised if that fixed it.

I'd pull the rest of the plugs and see if any others are oily, and if there's oil in the wells. If so, I'd start pulling valve covers and replacing gaskets. Something under there is leaking oil into the spark plug wells, anything from valve cover gaskets to the valve stem gaskets. If not, you might be in for a real treat: a full rebuild. If it's not coming from the valve train, that means it's coming up through the piston rings, yay!

 

[Fat Slob]

Release one or two bolts on the fuel rail I forget, pull up the rail so the injector clears the engine block, unsnap the injector from clip while holding a paper towel around it.

Do the other injectors pull out as well when you lift the fuel rail or can you isolate the one you want?

 

[Fat Slob]

I'd pull the rest of the plugs and see if any others are oily, and if there's oil in the wells. If so, I'd start pulling valve covers and replacing gaskets.

How difficult is this task?

 

[Adieu]

Do the other injectors pull out as well when you lift the fuel rail or can you isolate the one you want?

Yes the whole side but its not an issue, they stay on the rail

 

[deweysmith]

Do the other injectors pull out as well when you lift the fuel rail or can you isolate the one you want?

They do come up, but they are still attached to the fuel rail so they don't (shouldn't) release any gas. The injectors aren't under compression, so they are just held in the intake manifold by their o-rings and the fuel rail itself.

How difficult is this task?

Service manual puts it at 4.6hrs to replace the valve cover gasket. The valve seals are 2.7hrs plus the valve cover gasket time. The driver's side is pretty straightforward, the passenger side requires draining the cooling system if you have rear climate control because those hoses need to be disconnected.

It's a solid weekend job, but it can be done.

The valve seals are harder. You have to ensure the valves don't fall into the cylinder, and if they do, you get to remove a head, yay! It's pretty unlikely it's the valve seals, though. More likely the seals around the spark plug wells that you change along with the valve cover gaskets.

 

[Adieu]

How difficult is this task?

Dont you have the evil flimsy plugs on an '04???

Even without that its a pain in the ass for a couple hours.


Oh here's thr fastest one, disconnect the power clip to the injector on #6 and start the truck. If its the injector, your symptoms should remain fairly unchanged. If stuff gets worse, your injector was working (at least to some extent lol).

Still its almost certainly either the injector or the coilpack on #6.

 

[deweysmith]

Dont you have the evil flimsy plugs on an '04???

Even without that its a pain in the ass for a couple hours.

Oh, yeah. You do.



Definitely eliminate everything else first then because pulling plugs is not so easy.

 

[deweysmith]

WAIT just kidding, isn't it a 2V and not a 3V? The 2V never had the spark plug issue, only the 3V.

 

[bnicov]

Was the oil on the electrode end or the the insulator end?? If the oil is inside the engine, you are looking at bad piston rings or valve seals. If the oil is only on the body of the plug, then you are looking at valve cover gaskets which is doable.

 

[Fat Slob]

Was the oil on the electrode end or the the insulator end?? If the oil is inside the engine, you are looking at bad piston rings or valve seals. If the oil is only on the body of the plug, then you are looking at valve cover gaskets which is doable.

The oil seemed to be more on the body of the plug.

Also - quick update: As previous poster suggested I unplugged battery cable to let computer reset and synch the new plug I installed. Immediately after reconnecting battery the truck had same issues. However, over the course of the following day the miss/shake got noticeably less and by end of day it was completely gone. I have driven it since Friday and it's been running great and no codes, knock on wood. I guess its possible the computer did correct the timing with the new plug... I will pretend the issue is fixed and won't return..

 

[deweysmith]

The oil seemed to be more on the body of the plug.

Also - quick update: As previous poster suggested I unplugged battery cable to let computer reset and synch the new plug I installed. Immediately after reconnecting battery the truck had same issues. However, over the course of the following day the miss/shake got noticeably less and by end of day it was completely gone. I have driven it since Friday and it's been running great and no codes, knock on wood. I guess its possible the computer did correct the timing with the new plug... I will pretend the issue is fixed and won't return..

The learning computer can compensate for a LOT of weird engine anomalies, it's pretty smart. It allows for a really efficient and specific tune for your specific engine weirdness, since no engine performs identically.

It can also be super weird when that weirdness changes or goes away.