Hi Everyone,


Long-time reader, first time poster. I've searched this forum but have not seen exactly what I'm dealing with and am looking for help. I'll try to be as detailed as possible, but please be kind if I miss something! Also, I'm not the best with knowing what each part is called, so forgive me if I call something by an incorrect name.


I have a 2009 F150 Supercrew FX4 (5.4L 3V). I bought it approximately 18 months ago and it has about 167,000 miles on it (I've only put on about 10,000 of those miles). When I bought it, I knew both exhaust manifolds would need to be replaced, as it had a nasty exhaust leak and I could see that they were warped. I decided to purchase JBA shorty headers and do the install myself this past summer. Turns out, the headers did not align with the completely welded exhaust at all, so I removed the exhaust and added a Walker kit from Rockauto. I opted to use clamps instead of welding, at least in the short term, just in case something went wrong. I still had an exhaust leak that I could not get to go away, but figured I would drive it anyway and look at it again in the spring.


After about 3 months of driving with the new exhaust and headers, my check engine light came on and code P0430 was the only code that showed up. After doing some research on to potential causes, I decided to inspect the headers and see what, if anything, was going on. Turns out I did not install the headers properly and blew out both gaskets. I didn't know there was a special sealing bead and had to install them in a specific way until after they were on. I had tried after about a month of driving to re-install without fully removing them, but I apparently did not do it right that time either. Not wanting to take another chance with a bad install (and seeing the char marks on the engine right by the engine block heater), I ordered replacement exhaust manifolds. I took everything off again, put on the new manifolds, and starting bolting it back together when I heard something ratting in the drivers side catalytic converter. I turned it over to dump out what I thought was dirt, but it was the actual media of the converter. Turns out I fried it, as well as both O2 sensors on that side. I bought another converter and new O2 sensors, finished bolting everything back up, and fired it up.


It shuddered something fierce and felt like it was constantly misfiring. I put the code reader on it again and it said P0430 permanent this time. I tried to erase the code, but it will not erase. I had the battery disconnected for several hours and that didn't erase it either. Just today I replaced all 8 spark plugs and tried again, but it didn't feel any different and I still can't erase the code. I have Forscan and a cable for it, but it did not show any misfires or any faults across any system (besides the normal monitors not ready from having the battery disconnected and the codes erased).


I'm now at a complete loss for what to do and need whatever advice you can collectively give. From when I've bought the truck to date and related to the exhaust, I have replaced all 8 spark plugs twice, all 8 COPs, all 8 fuel injectors, the serpentine/drive belt, both exhaust manifolds (new studs and nuts twice), and the entire exhaust system (from where it connects to each manifold through where it exits at the back of the truck). I have not replaced the COPs or fuel injectors since I started having issues.


Beyond the exhaust, I have replaced most of the front suspension (both IWEs, both steering knuckles, both upper control arms, both lower control arms, driver's side half-shaft, both lift blocks (went from 2" to 1.5" - stupid mistake, don't ask), both struts/springs, new bolts all around, including a worthless alignment kit for the LCA's because I had to cut through the original bolts to get them off), new pads and rotors all around, all new wheels and tires including the spare, both front brake dust shields, the starter, the oil pan (added a fumoto oil drain valve, oil dipstick and tube, rear backup sensors, the module that controls the rear backup sensors, most of the parking brake hardware (need to replace the rear brake dust shields so everything is actually connected), both headlights, both tail lights, and both fog lights, and replaced both front calipers.


I have upgraded to a Raptor-style front grill with the amber lights, added clearance marker lights, added an LED bar behind the grill, two LED small rectangular lights by the license place holder in the front, added two LED small rectangular lights to the rear for backing up in the dark, replaced interior lights with LEDs, installed an aftermarket radio, sub, and speakers, added a truck cap, added LEDs to the bed, upgraded with heated tow mirrors, and installed the engine block heater.


For fluids, I've done a brake flush, several oil changes, a coolant drain and fill, and added fuel injector cleaner a couple of times.


Again, any and all help is appreciated.

 

Long story short, it takes 3 complete drive cycles for it to clear. For F150's, it's after 2009 and after M/Y's.

Here's some instructions right from the books of the Fordification:

 

Thank you for that information - I honestly did not know it!

Since it is still shuddering and feeling like it is misfiring, I am hesitant to drive it unless that will/should also go away with driving. Any advice for that?

Thanks again!

 

Now I don't want to scare you, but you might as well be prepared:

First things first, you have a 5.4l 3v V8, which have variable cam tensioners and guides that like to disintegrate, especially at higher mileages.

I would recommend checking your oil pressure and possibly popping open the valve covers to see how things are there. It might not be too long before that goes.

Also, I'd replace the injectors by now.

As far as the gaskets blowing out, it might have been the back pressure from the clogged cat.

Try to stick with OEM Ford parts, if possible. Except for the oil pump; go with a Melling high flow oil pump if needed.

So here's a couple questions:
1. What brand spark plugs?
2. What brand cat converter(s) and o2 sensors? Manifolds?
3. Did you do a back pressure test on both sides on the exhaust system?

 

I replaced the injectors about a year ago. Should I replace them again? Is it possible I did something to them when the gaskets blew out?

Spark plugs are always Motorcraft (I learned that the hard way on a different truck).

I used a Walker brand catalytic converter. It was an exhaust kit from Rockauto. After I destroyed the first one, I replaced with the same to make sure it would all fit together without replacing more parts that I’ve already replaced.

O2 sensors are Bosch.

New manifolds are Ford brand (definitely not Dorman).

I have not done any back pressure testing at all. I’m not sure how to do that or if I need to take it into a shop. But since I’ve just replaced the cat again, I wouldn’t think it would be clogged. I could be wrong, as I’m stating my assumption only and am open to being educated.

I’ve thought about the cam tensioners, but wasn’t sure if they would cause this issue. I’m familiar that they can go, but not much beyond that.

I have not checked oil pressure either or opened the valve covers. I’ll be honest and state that this is territory I’m not at all familiar with. If there are dome nice how-to’s, I’m willing to give it a go.

Thanks!

 

That's good on the injectors. I take it they are OEM Motorcraft injectors?

That P0430 has to do with failing/plugged cats or an exhaust leak.

From the symptoms you are describing, it sounds as of there might still be a restriction. I would do an exhaust back pressure check. I would also disconnect the muffler to see if that improves anything too. I'm wondering if chunks of the failed cat aren't giving you problems downstream like inside of the muffler. You never know.

To do a back pressure test, rent/borrow an exhaust back pressure test kit from your local auto parts store, remove a o2 sensor, and screw the adapter and gauge in. Start the truck and see what you get. Ideally, there should be minimal pressure.

Also, is this a 50 state (aka CA cert) with 4 o2 sensors, or just normal NON-CA setup?

 

Ah, good point about chunks possibly downstream - I didn’t think about that and will check it out this coming week. I’ll also rent the back pressure gauge while I’m doing work down there.

I had to double-check and it turns out I bought Bosch injectors. Should I swap them for Motorcraft or are the Bosch ones decent?

 

Bosch makes most Motorcraft injectors, so they should be fine.

 

The fault code should actually be describes as indicating a non-functioning, that is, a chemically "dead" converter. It has nothing to do with restricted or "plugged" converters.

 

What’s bugged me about this whole situation is that I knew the first one was dead and so I put on a brand new one and the symptoms did not get better when I first fired it up with brand new O2 sensors as well. I reached out to the manufacturer who is insisting that the issue is not the new converter, but it is difficult for me to believe that a brand new one immediately clogged as soon as I started up the truck the first time. That’s why I replaced the spark plugs again and am looking at other components that could be bad. So far, throwing brand new parts at it is not making anything better regarding the really bad shuddering/mis-firing feeling.

I just ordered an exhaust back pressure kit, as none of the stores in my area have one available to loan. I’ll also try to check further downstream for any chunks from the failed converter.

Stupid question that just occurred go me: I have been focusing only on the drivers side cat and O2 sensors because that’s what the code is telling me. Should I be looking at the passenger side as well? I didn’t hear anything rattling on the passenger side and didn’t think to investigate it further.

Oh, and I can’t remember if I mentioned this in my original post, but Forscan did not show any faults at all after idling for about 25 minutes. Granted, I did not do any driving and all my monitors were reset from trying to clear the code and having the battery disconnected.

As always, thanks for all the help!

 

Yes, I would recommend checking both sides.

Idling and driving are two different scenarios. That is why there is drive cycle monitoring and why it's important that everything be monitored if there is a problem.

 

It has been a long time over, 20 yrs, but Midas did a back pressure check for me by boring a hole in the exhaust pipe and holding a pressure gauge that had a rubber tipped inlet to the hole. then they welded up the hole. Using that method you can check the back pressure anywhere in the system. I would be wondering if the muffler is plugged with catalyst like has been suggested.

 

After reading this thread, I really want to see pictures of your truck?!

 

Alright, I’ll take some pictures this week and post them to this thread. The back pressure gauge I ordered arrives sometime tomorrow, so I’ll take pictures while I’m out there.

 

Front end with Raptor-style grille and tow mirrors (driver’s side is folded to allow easy access while I’ve been working on it).

Clearance marker lights.

Close up of grille. There is a light bar behind the letters.

LED lights by license plate holder.

Stubby antennae.

New suspension parts. I have to swap the UCAs for longer ones because they are rubbing the spring just a bit.

Side view with cap (yes, it is brown!).

New wheels and tires and front calipers.

6 switches that control all my auxiliary lights. I opted to not have them controlled with my headlights - because I’m weird!

Aftermarket radio. Nothing too fancy, just hated Sync.

Aftermarket powered sub under passenger side rear bench.

Rear view showing both LEDs under the bumper.

Close up of one of the LEDs under the bumper. I tried high heat paint on the exhaust, but I didn’t do it properly so it is flaking and burning off.

Close up of trailer hitch cover. It lights up with my brakes.