Vacuum Leak I think!?!? Or Failed Valve?

When you pull the plugs, label which bore they came from, post pics, I would like to see how they are burning please,
also take a nice little bright flashlight and look down the bore ....pics of that if you can...
Hope you don't see anything like this...
31473703.jpg
 
Sapperfire said:
When you pull the plugs, label which bore they came from, post pics, I would like to see how they are burning please,
also take a nice little bright flashlight and look down the bore ....pics of that if you can...
Hope you don't see anything like this...
Click to expand...

Last time I looked there was a little oil - Im hoping its still a little.. and maybe thats the problem.
 
Any sort of foreign matter on the plug tips means the plug is fouled, a fouled plug will misfire, if you have oil on the plug, generally it's piston rings, this can be double checked by a compression test.
 
Sapperfire said:
Any sort of foreign matter on the plug tips means the plug is fouled, a fouled plug will misfire, if you have oil on the plug, generally it's piston rings, this can be double checked by a compression test.
Click to expand...

I was thinking valve cover gasket
 
If the valve cover bore gaskets are leaking oil onto the plug, you'll see the oil on the bore wall when you look in there...and it'll pool around the top of the plug...not very commonon our motors because of the angle of the heads
 
Sapperfire said:
If the valve cover bore gaskets are leaking oil onto the plug, you'll see the oil on the bore wall when you look in there...and it'll pool around the top of the plug...not very commonon our motors because of the angle of the heads
Click to expand...

the reason I thought valve cover gasket is cause i saw the oil running down the rubber boot
 
97MarkVIIILSC said:
the reason I thought valve cover gasket is cause i saw the oil running down the rubber boot
Click to expand...

Not uncommon to need a valve cover gasket.

A miss is more noticeable at idle.

COP are known to go bad if they are oil soaked.

Fix the miss before you worry about the valve cover sapp has it covered.
Reread his posts, follow his advice

A gen 2 is known for all of this.
Welcome to the land of lincoln :)
 
ford nut said:
Not uncommon to need a valve cover gasket.

A miss is more noticeable at idle.

COP are known to go bad if they are oil soaked.

Fix the miss before you worry about the valve cover sapp has it covered.
Reread his posts, follow his advice

A gen 2 is known for all of this.
Welcome to the land of lincoln :)
Click to expand...

Im guessing this would explain the drastic decline in gas milegae at idle??

I'll have to leave the car sitting Friday night until mid-day sat, or sunday to get the plugs out :( Fuking thing stays hot for so long!
 
The decline in mileage at idle is because the car is not moving. How can it get xx MPG when it is not adding any miles on it?
 
97MarkVIIILSC said:
Im guessing this would explain the drastic decline in gas milegae at idle??
Click to expand...
Yes a miss will kill your mileage.
97MarkVIIILSC said:
I'll have to leave the car sitting Friday night until mid-day sat, or sunday to get the plugs out :( Fuking thing stays hot for so long!
Click to expand...
Were some gloves :)
You can use any plug to check for spark, you don't have to pull one.
My 97 just needed one COP.
You might too....you just have to find it.
I would check that first.
Kiss...keep it simple stupid ;)

Some around here drive with a good COP in the trunk so if there on a trip...they can fix the stupid car.
They are known to f@ck up.
 
LaserSVT said:
The decline in mileage at idle is because the car is not moving. How can it get xx MPG when it is not adding any miles on it?
Click to expand...

No I get that, but this is a very rapid decline...Ive watched it drop 1-2MPG at a redlight (within 50miles of resetting tho..) But still, never seen it affected this much while stopping
 
ford nut said:
Yes a miss will kill your mileage.

Were some gloves :)
You can use any plug to check for spark, you don't have to pull one.
My 97 just needed one COP.
You might too....you just have to find it.
I would check that first.
Kiss...keep it simple stupid ;)

Some around here drive with a good COP in the trunk so if there on a trip...they can fix the stupid car.
They are known to f@ck up.
Click to expand...

Hahah I wasnt worried about getting burnt, the metal swells and I cant torque the plug out.. well i dont WANT to torque it and have it break off or something in the bore.

So to check this, do I just check them while the engine is running? take one out at a time, put a fresh plug in and see if it sparks?
 
97MarkVIIILSC said:
Hahah I wasnt worried about getting burnt, the metal swells and I cant torque the plug out.. well i dont WANT to torque it and have it break off or something in the bore.

So to check this, do I just check them while the engine is running? take one out at a time, put a fresh plug in and see if it sparks?
Click to expand...

Clicky clicky

Just use a new plug if you can't pull your plugs...do this first if its not a COP follow the rest of sapps advice.

Simple a pie. ;)
 
97MarkVIIILSC said:
No I get that, but this is a very rapid decline...Ive watched it drop 1-2MPG at a redlight (within 50miles of resetting tho..) But still, never seen it affected this much while stopping
Click to expand...
Thats because you just reset the mileage counter. Its a function of TIME and consuption. If you reset the mileage then drove xx miles then STOPPED for xx miles your car burns fuel while it sits so of course the MPG reading will drop while you watch it when stopped. This isnt fuggin rocket science here.

If I reset my MPG then drive 70 miles and then stop, I can watch it drop a tenth every few seconds.
 
LaserSVT said:
Thats because you just reset the mileage counter. Its a function of TIME and consuption. If you reset the mileage then drove xx miles then STOPPED for xx miles your car burns fuel while it sits so of course the MPG reading will drop while you watch it when stopped. This isnt fuggin rocket science here.

If I reset my MPG then drive 70 miles and then stop, I can watch it drop a tenth every few seconds.
Click to expand...
lol
Hes a n0000bbbb!!!

Plus form the east coast......cut him some slack......:D
 
LaserSVT said:
Thats because you just reset the mileage counter. Its a function of TIME and consuption. If you reset the mileage then drove xx miles then STOPPED for xx miles your car burns fuel while it sits so of course the MPG reading will drop while you watch it when stopped. This isnt fuggin rocket science here.

If I reset my MPG then drive 70 miles and then stop, I can watch it drop a tenth every few seconds.
Click to expand...

Thank you for enlightening me ohh wise one. I've seen you harp on noobs before, but before you get carried away I suggest that you not try that game with me buddy-boy.

I understand the simple equation of time/consumption - If I drive X amount, and then stand for 30 minutes, the mileage traveled will average out opposed to gas consumed. HOWEVER, I clearly said.. it was doing it MORE DRASTICALLY then before - so apparently I notice how this works, and now that it is behaving differently "coincidently" at the same time I am noticing an issue I was just tying them together.
 
I would suggest that you have your car smoked. That is the sure fire way to find all vacuum leaks. If you are not far from Cambridge, go to Tom and Ray Magliozzi's garage. Tell them Greg in Houston referred you and they will get a chuckle out of that. I called them on my Mark last year.
 
GMAN said:
I would suggest that you have your car smoked. That is the sure fire way to find all vacuum leaks. If you are not far from Cambridge, go to Tom and Ray Magliozzi's garage. Tell them Greg in Houston referred you and they will get a chuckle out of that. I called them on my Mark last year.
Click to expand...

Much appreciated - I am from Boston originally (actually lived in cambridge for a little bit) but now I am down South atleast for now
 
97MarkVIIILSC said:
Thank you for enlightening me ohh wise one. I've seen you harp on noobs before, but before you get carried away I suggest that you not try that game with me buddy-boy.

I understand the simple equation of time/consumption - If I drive X amount, and then stand for 30 minutes, the mileage traveled will average out opposed to gas consumed. HOWEVER, I clearly said.. it was doing it MORE DRASTICALLY then before - so apparently I notice how this works, and now that it is behaving differently "coincidently" at the same time I am noticing an issue I was just tying them together.
Click to expand...
Its not a game Sparky. I have been trying to help you and have given you good advice. I am also trying to save you a wild goose chase and looking for chit that ain't there.

If you are telling me when the car ran perfect you reset the MPG counter, then drove a specific amount of miles driving a very specific way and timed the EXACT amount of time the car was stopped THEN repeated the exact miles/time/driving style now and its dropping faster then I would say you are full of chit.


Not being a dick (well totally) but take all this in to consideration. Lets say you drove 50 miles after a reset. That drive was 48 miles on the highway doing 65 MPH. Then you come to a stop after a mile or so on side streets, then you sit at a light for a minute or so. You will watch the MPG drop slower because you spent much more of that time getting a higher MPG.
So you reset it and drive 50 more miles. This time you accelerate hard, drive on some side streets then hit the highway. On the highway you happen to hit some downhill runs then you get off the highway and sit at another light for a minute or so. As you approach the light the average may be the same since the computer has had a short cycle to compute the MPG but when you come to a stop it drops faster because you just spent more of that 50 miles at a higher fuel consumption so the overall average over TIME has dropped.

The only way the car will burn more gas at a stop now then it did before would be because you are leaking fuel.

I am sure you are not leaking fuel but misreading your computer.


I still stand behind my IAC diagnosis. You say the car runs fine when moving and has a SLIGHT and RHYTHMIC stumble at idle. That tells me your IAC is sticking. Yeah a vac leak is possible too as is a misfire due to bad coil/plugs but the IAC is much more likely. Go to any Mustang site and 90% of the idle stumble problems on stock cars that have over 60k or are over 4 years old have a bad IAC. The averages are close to the same here.
 
LaserSVT said:
I still stand behind my IAC diagnosis. You say the car runs fine when moving and has a SLIGHT and RHYTHMIC stumble at idle. That tells me your IAC is sticking. Yeah a vac leak is possible too as is a misfire due to bad coil/plugs but the IAC is much more likely. Go to any Mustang site and 90% of the idle stumble problems on stock cars that have over 60k or are over 4 years old have a bad IAC. The averages are close to the same here.
Click to expand...

My car idles one notch below 1k, it sometimes hangs when I let off the gas, but nothing crazy. I dont think its the problem. I do think my right front brake pad is sticking, since my car pulls to the right upon braking, and that might be affecting my mileage, but in regards to the decrease I was comparing my normal driving stlye each day and also noting the sudden decrease while conditions remained the same.
 
Ocassionally hanging idle and no CEL? Thats IAC.
 
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