Steps 1 and 2 checked out, so we can assume step 3 is the fix i suppose?
It’s hard to second guess over the web, and I’m concerned that the mechanic doesn’t even know that 3 and 4 are on opposite sides of the engine. But…
What happens in these engines is that the EGR runners plug up one by one. Finally you have all the exhaust from the EGR valve going into 1 or 2 cylinders instead of all 6. This throws the fuel mixture in those 1 or 2 off far enough to cause a misfire.
Sounds like the next step is to spend some time and money to open it up.
So only time causes the EGR runners to plug up with carbon? Meaning I’m not going to do the EGR runner cleaning only to have them clog up again in a few weeks/months due to another underlying problem? Theoretically it would take years and years for that much carbon to build up right
Theoretically yes, years. But it’s an old car with unknown (to me) history and condition.
A 2001 Mustang is almost 20 years old. It’s not like the car is going to last another 20.
Got it. Well at this point i’m probably just going to try the EGR passages cleaning and the induction cleaning service as well because i think i’ve tried pretty much everything that could be causing the plug fouling issue other than a serious internal issue (which is most likely ruled out.). Unless you think there’s any other possibilities (other than internal engine issue) I think i’ll just do what the mechanic suggested. Just to recap, i’ve done all o2 sensors, replaced MAF sensor, injectors, coolant temp sensor, coil pack, wires, air filter, fuel filter and fuel pressure regulator. Also vacuum leak test was performed and no leaks were present
Can you provide the compression numbers.
The computer knows how much fuel should be injected, the O2 sensor is detecting to much fuel,
The reading LEAN is how much less fuel is being injected than should be if it was running correctly.
You may want to test the connection between the spark plug #4 and the distributor. It is not getting the spark it needs. The most likely reason is inefficient burning in that particular location (too much fuel, too little air or not hot enough- not getting the right spark). I think you said you replaced the coil pack before you started having spark plug dry soot (no fluid on the plug probably indicates the reason is inefficient burning rather than a leak or plugged passages). Let us know if you can check the distributor to spark plug connection.
So you think cylinder 4 connector on the coil pack is bad? So just replace the coil pack again?
I don’t @James34 is on the right track
He says check the connection between #4 plug and the distributor
You don’t even have a distributor . . .
you have a coil pack
Right and in this case if the coil pack was bad all the cylinders would be fouling/misfiring not just one
Wrong, 3 separate coils in the coil PACK
Cylinders 3 and 4 share the same coil
What brand and style plugs are you using ?
Are you gapping them correctly .054 ?
Cyl 3 is rear on passenger side
Cyl 4 is front on drivers side
I’m using motorcraft OEM plugs which are pregapped. I considered the coil pack but it is a month old. I know new parts can go bad out of the box but this is highly unlikely. In addition if the coil pack was bad the car would almost certainly be throwing a code such as P0351 would it not?
Does the check engine light work ?
Comes on when key is in on position, goes out when engine running.
So, your Mustang 2001 is known to have problems with the same exact issue. The Coil pack has 2 wires running for each of the three packs one for the exhaust and one for the intake but both are firing at the same time. I also noticed that you had a thread running for the problem of overheating. So, looking at all coil pack more closely could reveal cracks or something that could indicate damage. I would test the wires (someone provided a diagram or an image for you I think) for resistance (I am not sure about the numbers you should get 1.4?) When the overheating occured, something might have been damaged in the connection between the coil pack and spark plug #4. I would not replace anything until tested and proved.
Um, no
Only one wire per cylinder
Yes, each spark plug fires on the compression and exhaust, but it still only uses one wire per cylinder, There’s only one spark plug per cylinder.
1 and 5 fire at the same time
2 and 6 fire at the same time
3 and 4 fire at the same time
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There are individual wires for cylinder 3 and cylinder 4 (often this is the culprit) one on the exhaust stroke and other on the compression stroke but both fire at the same time. Two things you should be aware of here: the engine ECU does not code for the misfire when this happens, it codes for sulphur emission (this is not to say that cleaning the EGR is going to solve the problem). The other thing is that the engine’s remaining cylinders will not experience any problems only 3 and 4. That being said, the problem could be anywhere from the coil pack to the spark plugs. Yet another issure frequently seen in most cars is that faulty spark plug can destroy a specific area in the coil pack (yes even new ones) or its connection. Best wishes. Let us know how it turns out.
Again, NO there is NOT a separate wire to fire on the exhaust stroke and another wire to fire on the compression stroke.
There is ONE wire per cylinder and it fires on both strokes.
Cylinder 3 fires on its compression stroke using its own wire
At the exact same time
Cylinder 4 fires on its exhaust stroke using its own wire
Cylinder 4 fires on its compression stroke using its own wire
At the exact same time
Cylinder 3 fires on its exhaust stroke using its own wire
I might ask again what the compression numbers are. They are stated to be excellent which may or may not be the case.
Quite often compression numbers are posted on this forum as being good when in reality they are anything but good. Just wonderin’ is all…
And yes, It_s_Me is correct (that’s what’s happening between the coil pack and cylinder 3 & 4- one wire for each cylinder both firing at the same time). Hope you solve the problem soon.