cyl. 4 misfire 01 taurus

[studentmechanic]

I actually already replaced the iacv and it didnt solve my problem. It always feels like only one clyinder is cutting out and it says it is #4 but no misfire readings are coming up on the datastream. I am going to do a compression test on it today, thanks, Matt.

[jfjohn]

my guess is that it's a bad injector , bad compression, or leaky intake or head gaskets. I guess a computer is possible but I doubt it.

[studentmechanic]

Well, I think I found my problem. I took a compression reading across the front three cylinders and this is what I got. Cyl 6- 90 running, 120 cranking. Cyl 5- 120 running, 180 cranking. Cyl 4- 70 running, 90 cranking, and 120 cranking when I added oil to the cylinder. So somehow this 01 taurus already has fried rings!!!! It seems kind of odd to me but I guess it is what it is! Thanks, Matt.

[jonmark1985]

Not always rings.

Check camshaft lift; that a lobe isn't wiped or a push rod isn't bent.

[studentmechanic]

Even though the compression increased when oil was added to the cylinder? I thought that was a definate sign of bad rings. Thanks, Matt.

[jfjohn]

if the rings are bad, it's probably because it's the dohc. the 3.0 sohc vulcan is bullet proof. The vulcan seems to be more durable.

[jonmark1985]

Originally Posted by studentmechanic

Even though the compression increased when oil was added to the cylinder? I thought that was a definate sign of bad rings. Thanks, Matt.

Then it could be Matt

I worked in a parts store for year and a half, I always heard people make the guesses for their problems, eg. if a starter didn't work it was the solenoid, alot of the times on these paticualr things it never was what they thought. Rings are often blamed for low compresion but seldom are ever the cause. I've tore apart several motors with 150,000 miles that still had hone marks on the walls and ring gaps that were near perfect. So thats why I wanted you to rule out other factors before you start on the rings.

[jfjohn]

before spending any more money, I would put a quart of marvel mystery oil in the crankcase with an oil change. Put some in the gas too. if anything is getting stuck, marvel will free it.

[zed322002]

Matt,
It's been few days since you visited forum so you might have fixed the problem. Unfortunatelly for me I have exactly the same thing happening to my Ford Taurus 2002. I have 3.0 V6 DOHC. It starts missfiring when it warms up a little; it misfires only when it idles; if it misfires very badly when I'm on the stoplight I put it in parking and it goes away in 90%. Engine diagnostic code says that Cylinder #2 misfires.
I changed my spark plugs and it still does the same thing. At Ford dealership they mention that it could have been spark plugs or ignition module. I'm gonna play with it on saturday to see what other posible causes those might be.
Please let me know if you figured it out, maybe that will save me some time.

Ps. Thank You all forum members for your valuable input
Thanks
Zed

[reinhart36]

Originally Posted by zed322002

Unfortunatelly for me I have exactly the same thing happening to my Ford Taurus 2002. I have 3.0 V6 DOHC. It starts missfiring when it warms up a little; it misfires only when it idles; if it misfires very badly when I'm on the stoplight I put it in parking and it goes away in 90%. Engine diagnostic code says that Cylinder #2 misfires.
I changed my spark plugs and it still does the same thing. At Ford dealership they mention that it could have been spark plugs or ignition module. I'm gonna play with it on saturday to see what other posible causes those might be.

Zed

I too have a 2002 taurus with the 3.0 V6 DOHC, and it is also doing this exact same thing.

If I keep it in drive at a stoplight for more than about 20-30 seconds, the engine starts running very rough and the check engine light begins to flash. When the light turns green, it feels like a cylinder is missing and power is low. As I drive, the problem disappears after about 30 seconds or so.

Engine diagnostic codes report misfire on cylinder #2.

I replaced my plugs and wires, to no avail. I also notice that it runs a little rough at idle all the time, even when the check engine light isn't blinking.

A mechanic said I'm getting low compression in that cylinder, but I don't see how this problem can just start predictably and go away predictably if it is caused by low compression (which would always be present, I think).

Any ideas?

Thanks!
Eric