2002 Lincoln mountaineer missfire and low power

[2004LB7]

My brother and I picked up a Lincoln mountaineer for the cost of a title transfer and tax at DMV

But.... It has multiple missfire codes, low power and ticking around #8 cylinder

It uses the ford 4.6L V8 which is well known for both valve train ticking and missfire. The previous owner had a mechanic look at it shortly before giving it to us and the paperwork stated that there were multiple missfires detected during testing. Compression check supposedly good with only one recorded reading of 180 psi. Swapped cool packs around and sent him on his way

So far we found a bunch of oil soaked coil packs and boots on the driver's side which is in indication of a bad valve cover gasket.

Removed the valve cover and checked the lifters and cam followers, etc. The two lifters for #8 where stiff and would not compress without considerable force. Everything else looked good

New coils, boots and plugs arrived today so we are starting to put the driver's side back together. We are going to put silicone grease on all of the coil high voltage connections and boots

The passenger side had no oil or coolant in the plug holes. Just a little corrosion and debres. But we are replacing all of that anyways.

Most of the connectors for the injectors and coil packs are cracked or have missing tabs. Someone before us even glued a few of them on that where broken.

My brother intends on keeping this one as he needs an AWD/4WD vehicle and this one is in pretty good shape for 160k miles

Other then testing the injectors, what else should we be looking at for multiple random missfire codes that come back in less then a mile of driving that I may not have covered above?

Thanks Jason

 

[Anotherduramax]

Big thing with those is clogged catalytic converters. Tap them with a hammer, all the exhaust gassed run down the log so when they clog they will cause a misfire on cylinders 1&2 and 5&6. These things are labeled weird (to me anyways) as far as cylinder orientation. The other issues are the cam phasers, I might drain the oil and run a little atf in it to see if it would free up the lifters. (I was corrected below, looks like Cam Phasers were not used until 2004, lots of knowledge on this forum!)

 

[Benny315]

weak fuel pump or plugged filter could also do it. Sounds they were trying to figure it out and gave up. Crank/cam sensor, air leak on intake side, broken vac hose, plugged cat, could all cause misfire

 

[Chevy1925]

^^ seen that many time in the cop cars i wrenched on. usually they rattle but i had a couple that didnt rattle, just felt way under powered. one set a code for cat performance, other never set anything. if its bad enough, i can see it setting codes for it.

like said, dead blow hammer tap to see if the element rattles around inside will tell you if they are shot and blocking the exhaust.

i dont remember if those have cam phasers or not. if they do, they can cause issues and miss fire codes as well.

it wouldnt hurt to look into replacing all the lifters. they like to have their oil changed regularly. if not, you will get junk built up in them and they aint happy.

pulling plug threads is a real threat on those as well if it still has factory original heads. make sure you are not getting blow by around a plug or two. i was always particularly careful in never cranking down those plugs and always using anti-seize. just a little snug to crush the washer and let it be. plugs only seem to be good for about 60k as well using just motorcraft copper cores. i tried more expensive plugs in them like platinum or iridium and they never seemed to run as well or would come back with miss fire codes.

fuel pumps dont "give out" like the gm trucks. they get weaker as they heat up or as the tank runs low. at times ive had to let a car idle all day in the parking lot and then take it for a test drive with the fuel pressure gauge hooked up to see pressure below where it should be. generally the car falls on its face in the upper rpm or starts spitting and sputtering though. can feel like a plugged exhaust issue when its not

i serviced alot of crown vics up to the 150-200k mark before they were pulled from service and new ones given out. these were 99-07 crown vics. they were ragged on every day, a few officers thought they were ricky racer. never had an engine go, only transmissions on a few different cars (id say like 10 cars across the northern part of the state).

 

[2004LB7]

Thanks. Lots of good stuff to look into.

I think the heads are the 9? Thread version. This vehicle has been in our extended family for most of it's life. My uncle several years ago changed the crank and rod bearings. When he opened it up he saw that someone was in it before him as the pistons where not all a matching set, or different colors or something. I think it had some work done and new heads put on it as it has the additional threads for the plugs.

My uncle put new timing chains, tensioner, etc when he rebuilt it. I don't remember seeing phasers when he had at all apart.

It does look like it has an exhaust leak right behind the #8 cylinder the shows little puffs of smoke when cold. I've read these engines like to rust out their exhaust manifold bolts and leak. Anyone else experience this or have had to repair one? Seems like it would be a bitch to fix with no room to work on it back there. Or am I looking at the EGR tubes or something else? Haven't dug into that problem yet

We might replace all the lifters too. Not toe hard to do. Don't have to remove the cam or anything major. So if it continues to be an issue we will order up a whole set

I'll keep you posted

 

[2004LB7]

Made a little test rig for the injectors. A piece of hose, valve and air chuck. Clamp the injectors in the hose, fill the hose with fuel and pressurize it with 50 psi air. Fire off the injector and watch the spray pattern.

Only one looked good. Most ok-ish and one or two not so good. Going to look at injector prices now.

Got most everything cleaned up and I'm going to reassemble it for now. See how it runs until the next bag of parts shows up

 

[2004LB7]

Got it back together. Found the exhaust leak on the connection between the manifold and cat. Got that fixed.

New plugs and COPs seems to have cured the missfires. At least for the short drive I did. Still seems low on power so I am going to pick up a fuel pressure gauge and see what we get.

 

[TheBac]

Just my opinion, the cat is probably plugged up, too.

 

[2004LB7]

Oh, yeah. I forget to mention. We banged on the cats with a rubber mallet and they sounded solid. No rattling or any excess noise

Thoughts? Still a possibility or unlikely?

 

[TheBac]

Well, check the fuel pump first, but I do know a plugged cat will throw random misfire codes. Darn Grand Prix's love to do that.

 

[Benny315]

Do the misfire codes refer to one side of the engine or they all are misfiring? Can you see the O2 sensors working with your scan tool? After your short drive did you notice one cat starting to glow or foul smell? Does the exhaust seem restricted at the tailpipe? You should have dual cats, but would think you would be getting some p0420 codes as well.
I don't trust the hammer trick to much as I have seen plugged cats due to mostly gasket material or debris getting in from exhaust manifold gasket blow outs and broken manifold bolts or even pieces of the doughnut.
If none of that and what others mention, I would lean more towards fuel or ignition. Check the engine ground to the body as well.

 

[2004LB7]

The missfires haven't come back since the new COPs and plugs. When we did have them they where only on 5,6,7 & 8. After clearing and taking it for a short drive it had #8 (P0308 pending) and P0300

The ticking that we had at times goes away but always returns. Stethoscope tells makes us think it is at #2 & #7 but hard to tell. Going to do an oil change soon so crossing my fingers. Still think we need to change the lash adjusters/lifters. And injectors too just to be safe

The exhaust doesn't seem restricted. It has the cats on each side and one on the center just behind the "Y" so three total. Before tightening up those loose exhaust bolts, the leak was only noticable when the engine was cold and at high idle so it didn't seem like it was under much pressure. Once the rpms came down you couldn't tell there was any leak other then maybe à little more noise.

We picked up the fuel pressure gauge but it doesn't have the right fitting for this vehicle so we now need to hunt down and adapter.

My scanners/code reader doesn't read fords so I am borrowing one. I had to return it for a bit but from what I remember, it did show O2 sensor readings. I'll look at them again when we get the scanner back in hand

 

[Chevy1925]

You won’t notice the plugged cats at idle. Even high idle. Same way as a fixed vane turbo builds no boost; the flow from intake to exhaust is no where near enough to cause decent back pressure.

That said, I’ve never had a cat “plug” on these but doesn’t mean it don’t happen. It was always the element coming apart inside, turning, and then plugging it.

If the injectors “look” that bad. It’s going to kill power. I’d get all the stuff you found fixed, then concern yourself with the lower power. Like I said though, just don’t expect much from that 4.6. They are gutless

 

[2004LB7]

So if the "hammer" test is not always reliable and there isn't enough exhaust flow to notice excessive back pressure, how does one check the cats?

Do you remove each one and try and inspect them? Do you just replace them anyways? Put a pressure gauge on the exhaust and take it for a drive? Put a boroscope down the oxygen sensor hole?

 

[ZeroGravity58]

So if the "hammer" test is not always reliable and there isn't enough exhaust flow to notice excessive back pressure, how does one check the cats?

Do you remove each one and try and inspect them? Do you just replace them anyways? Put a pressure gauge on the exhaust and take it for a drive? Put a boroscope down the oxygen sensor hole?

Throw them in the trash and put antifoulers on the rear O2's

 

[2004LB7]

Sorry, I live in California and their smog laws. Has to pass the smog test

 

[Anotherduramax]

Easiest way is going to be just to remove them for a short time and take it for a drive to see if it drives better. The fords have a cylinder power balance you can watch also that is pretty cool, you might see lower output coming from the forward cylinders on it. I don’t think a temperature test would help the way these fail, but typically you should see quite a difference in inlet and outlet temp if it is working, if it’s clogged a bit I assume your actually going to see a pretty high temperature that’s consistent. The ones I have had fail are so bad they always rattle though.

 

[Benny315]

Ahh, the smog test. That sucks.
You can try the bore scope from the upper O2 holes looking down at top side of the cat's honeycomb. I have done it on a Hyundai once but was not happy with the picture quality of the small hand held snap on scope I have.
You might need to drive it more to get a code to pop up. If the misfires refer to one​ side of the engine than It could be plugged on that side. If you could see the 02 sensors reading and if one was reading different and was on same side as misfire than that would help confirm that it was one of the upper cat's and which one. The lower cat is after they come together and would be more of multiple misfire.
Dirty air filter, cracked bellows on intake tube, intake gasket, throttle body leak, plugged pvc valve, other things to look for.
I would just drop the pipes try to visually inspect/shake maybe even try blowing compressed air both ways see if any material comes out. Then when all else fails, I cut them open from the top side with die grinder pull the material all out then weld them back up like it never happened and use the 02 spacers, if it solves the issue get a new set and weld them back in

 

[NC-smokinlmm]

Shoot some sea foam into the cats and then go get them hot as hell by driving on interstate at 4000 rpm for 40 or 50 miles. That will clean them out. Lol.

 

[2004LB7]

Shoot some sea foam into the cats and then go get them hot as hell by driving on interstate at 4000 rpm for 40 or 50 miles. That will clean them out. Lol.

Haha, yeah we may do something like that before smoging it. Italian tune up style