Where to start?

[Jackler]

Hello, and thanks in advance for any help. I have found many answers to many questions on this site, unfortuantely I need a few more.
I have a 1997 Eplorer EB AWD, 5.0 ltr V8 with a 4R70W transmission. Here are my issues; I changed the oil about 500 miles ago, while chatting with the parts guy he suggested Seafoam treatment. Never using these products before, I asked the best way to use it and he suggested in the crankcase. So, I shorted the oil 1/2 quart and added a can of Seafoam buttoned everything up and drove away. 2 days later the car began to run very rough, rough idle, poor acceleration, poor starting and a smell of "burning plastic" in the cabin. Not sure if this is related or simply a bad coincedence.
I took it to the local Pep Boys and had them read the codes and received the following;
P0153 Bank 2/Sensor 1 Slow (O2 sensor I beleive)
P0174 Lean Bank 2
P0175 Lean Bank 2
P0305 (misfire)
P0306 (misfire)
P0307 (misfire)
P0455 Big Leak Evap.
P1152 Switch indicates rich

I replaced the plugs hoping to find some fouled (plugs and wires have 2000 miles on them), plugs in 1-4 looked good, 6 and 7 were oiley and smelled of fuel.
Looking around I also found that the spark plug wire boot on the #6 cylinder has a cut in it, the new plugs did help with startup, but there is still poor idle and what feels like a misfire. There is also the infamous "ticking" sound from the passanger side exhaust manifold (gasket or manifold). And lastly, there seems to be a leak in the gasoline "fill" tube, the tube that runs horizontal from the fill inlet before it heads south to the tank.
I know there are a littany of issues here, what I am asking is where to start? I do not have the funds to fix all of these problems right now, and there is an underlying transmission issue (P0782 2-3 shift) that needs to be addressed. Do any of you see a path that I should take, as in what should be done first, second, etc...
I plan to do as much myself as possible, so any help would be great.

 

[RomeovilleIL]

Change you oil and filter ASAP! Seafoam will loosen and break up sludge in the engine. The longest I've heard recommended engine operation with it in the oil is maybe 20 minutes. You don't want the oil pump or galleys to get clogged.

**
Once you get back to regular oil, clean or replace the fouled spark plugs (again). The misfires are the likely cause of your lean issue as the engine tries to adjust for rich on one side due to unburned fuel.

The leak at the filler neck is causing the P0455. Do a search - you can R&R or get a new one for $100.

 

[joecrna]

All of those codes are probably the same problem. Again Im thinking vacuum leak. The computer senses extra air at the O2 sensors so it richens the mixture. The misfire really could be a leaned out cylinder. Multiple sensors don't match because you are really getting extra unmetered air. The computer thinks some of the sensors are bad. Its a domino effect, computer gets bad info but trys to compensate. This throughs other info off and it agaian trys to compensate but still doesn't get the result it expects so now it decides sensors are bad.

Yes typically Seafoam is added just before the oil change. Its a cleaner rather than a conditioner or addative.

 

[RomeovilleIL]

All of those codes are probably the same problem. Again Im thinking vacuum leak. The computer senses extra air at the O2 sensors so it richens the mixture. The misfire really could be a leaned out cylinder. Multiple sensors don't match because you are really getting extra unmetered air. The computer thinks some of the sensors are bad. Its a domino effect, computer gets bad info but trys to compensate. This throughs other info off and it agaian trys to compensate but still doesn't get the result it expects so now it decides sensors are bad.

Yes typically Seafoam is added just before the oil change. Its a cleaner rather than a conditioner or addative.

+1 on checking your vaccuum lines. That burning plastic smell might be a vac line that got moved up against something hot while you were changing the plugs and wires.

A question -- was the check engine on before, or were these codes thrown after you changed the oil?

 

[joecrna]

Not just the lines. Intake gaskets, PCV lines, EGR, intake ducting after the MAF sensor, even exhaust leaks (remote possibility) can do this. Anywhere air can get in between the MAF and O2 sensors.

 

[Jackler]

Thanks, yes I changed the oil and filter when I changed the plugs yesterday. The parts guy told me that the Seafoam would "dicipate" and I could change the oil at regular intervals, ooops!!
Now, after the oil and plug change it still idles poorly, I took it back to Pep Boys and there were no codes, I had disconnected the battery to "clear" out any codes, and I guess they have not registered as of yet.

The CEL has been on for some time relating to the PO153, I had it checked about 3 months ago relating to a misfire before changing the plugs and wires the first time.

 

[RomeovilleIL]

The slow response code is usually the only code that truly indicates a O2 sensor is bad (most other O2 codes indicate the sensor has correctly read a problem in the exhaust system) -- try pulling and cleaning the sensor. Running with misfires it may have a lot of carbon built up on it.

 

[Jackler]

Checking for vacuum leaks seems to be the next logical step, I have looked at all of the hoses, lines, and connections I could see and nothing seems out of place. Is there a good way to check for vacuum leaks beyond the naked eye? Thanks

 

[joecrna]

I would never recomend this procedure as it is a bit dangerous but when desperate it has been done. Spray suspected areas with carb cleaner and listen for the engine to slow or bog. Spray area with Seafoam and watch for exhaust gas. Both of these are a little flamable but not too bad. You can also use starting fluid (ether). It is very flamable but if pulled into the engine through a vacuum leak the enginge will rev up and easily noticable.

 

[Jackler]

Ok, here is an update, again any help would be appreciated. I replaced the spark plugs, changed the oil and filter. As I was looking around for vacuum leaks (couldn't find any), I ended up finding the pcv valve and changed that out. I also did a Seafoam treatment at that point (always wanted to try that!). I ran the Seafoam through the pcv line and got all the results you would expect. After driving enough to get the CEL back on, I took it to Pepboys again and here is what came up;
P0156 (Bank 2, Sensor 2)
P1151 Fuel air meter (this one is new??)
P0306 (Cyl. 6 mis)
P0307 (Cyl. 7 mis)
P0174 (Bank 2 lean)

So, I have a couple new codes, but the same performance issues. Thoughts?

 

[joecrna]

Have no idea off the top of my head what the fuel air meter code is, MAF sensor? It seems that you may be making some progress. The other codes are at least consistant now. A lean condition, the misfires may be caused by the lean condition. When you changed the PCV valve did you thoroughly investigate the elbow at the valve, its common to crack here. Another high incidence failure leading to a vacuum leak and thus a lean condition is the EGR valve.

 

[ssp.interceptor]

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[Jackler]

Thanks for the feedback, and NO I don't have the bosch plugs in there. This explorer has 182,000 miles and the most recent plug change (and all past and future plug changes) I used the motorcraft plugs.

joecrna-I did inspect the pcv elbow, and it looked good, no cracking. Are you making reference to the vacuum leak being caused by the EGR valve, as in a crack in the tube, or a broken valve?

 

[Jackler]

Alright, another update. I brought the truck into a "friend of a friend" for a "pro diagnosis", here are his thoughts;
replace fuel pump, replace injectors 5-8. Comments are injectors 5-8 stuck open. Does this make sense? If all of that fuel is passing through, wouldn't all the codes be running rich, not running lean? Sorry if I am asking a dumb question.
Help!!

 

[ssp.interceptor]

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[Mountaineerbro]

This happen to me too. Sea form burnt out 3 of my spark plugs.....

 

[Jackler]

ssp-The "friend of a friend" works for a local repair shop, Pepboys I think, he told me he was certain this was the issue, not sure exactly which tests he performed. I will tell you I have become very suspect of my own diagnostic skills, therefore I went looking for help. Does this diagnosis make any sense?
I have been doing some reading on both the fuel pump and injector replacement, are either of them really scary, doesn't appear to be that way?


mountaineerbro-I to thought this was Seafoam related, now I think it was nasty coincedence

 

[ssp.interceptor]

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[ssp.interceptor]

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[joecrna]

I was thinking either a crack in the tube or the EGR valve itself. Injectors actually stuck open would cause an extremely rich condition. You'd smell it, your eyes would burn and the cats would glow red. How do I know this, another vehicle with dual ignitions lost the coil on one bank. Once the cat glows red for more than a very short time, its toast. Thats not to say the injectors aren't responding poorly, partially clogged and have a horrible spray pattern. As mentioned before, the only way to truely know is to pull them out and take them to a shop with an injector flow bench.

You seem to have lost the Evap code, did you fix it or is it just gone? I ask because I recently failed a CA smog test and ended up tracing it to a bad Evap system. Car ran like crap too. Mine was pulling in raw gas here (rich) but you could also get a lean condition from the evap system.

How about that burning plastic smell. Could have been a plastic tube, rubber tube or wire insulation. I know you've gone over all the tubes looking for leaks but might want to trace them again. Look at and feel all the sides. Also trace electric wires, especially those from sensors.

Dont suppose anyone near you has a flat diagnostics rate. That failed coil on one side of the V8 took almost 24 hours of diagnostic time to find. Your problem is proving very difficult to diagnose. I know funds are tight but you might want to punt this to someone else, depending on how much time you have and how soon you need this fixed.

If you're game Im sure we will keep trying to give you any ideas we can all come up with. Forgot to mention, changing the fuel filter is probably a good idea no matter what, than check the fuel pressure. The fuel pump and injectors should not be too difficult a DIY job.