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Problems with my Ford Escape

Zack

4 Doors 4 Life
Mar 21, 2004
6,297
20
NW Indiana
2002 Ford Escape 3.0L V6 150k on it
Ive never had an issue with this thing til yesterday.
Out of nowhere it starts running rough.
I find Cylinders 4 and 6 are dead.
So, I moved coil packs around, no change. I swapped plugs around, no change.
Compression test = pass
I even pulled the coils and watched the plugs fire outside the engine.

Both the upstream and downstream O2 sensors are stuck on .6v at idle for that bank.
The fuel trims are about -15% on both banks.

I am stumped.

Any insight is appreciated.

PS. I washed the engine a few weeks ago and have driven the car around a few times since this happened. I took all connectors apart, cleaned them and re-installed to rule that out. I also wiggled all wiring and the idle never improved.
 

rdsnake

formerly RD SNAKE
Mar 5, 2006
5,733
401
I doubt the cat will be that hot to visually see it. You could also drop the cats but as I recall they are part of the exhaust manifold and not easy to get off. Exhaust pressure gauge would be the easiest. All you need a o2 fitting with a nipple and a rubber hose, hooked up to the a normal pressure gauge. Does the car have low power with no check engine light?
 

Zack

4 Doors 4 Life
Mar 21, 2004
6,297
20
NW Indiana
I doubt the cat will be that hot to visually see it. You could also drop the cats but as I recall they are part of the exhaust manifold and not easy to get off. Exhaust pressure gauge would be the easiest. All you need a o2 fitting with a nipple and a rubber hose, hooked up to the a normal pressure gauge. Does the car have low power with no check engine light?

It has almost no power to get out of its own way and doesnt throw any codes.
 

l0wb00st

Overbuild It, Or Don't Build It
Jan 29, 2012
1,168
94
NW Suburbs
2002 Ford Escape 3.0L V6 150k on it
Ive never had an issue with this thing til yesterday.
Out of nowhere it starts running rough.
I find Cylinders 4 and 6 are dead.
So, I moved coil packs around, no change. I swapped plugs around, no change.
Compression test = pass
I even pulled the coils and watched the plugs fire outside the engine.

Both the upstream and downstream O2 sensors are stuck on .6v at idle for that bank.
The fuel trims are about -15% on both banks.

I am stumped.

Any insight is appreciated.

PS. I washed the engine a few weeks ago and have driven the car around a few times since this happened. I took all connectors apart, cleaned them and re-installed to rule that out. I also wiggled all wiring and the idle never improved.

First thing i'd do is Check the Injectors. A missfire will cause the fuel trims to go negative
 

rdsnake

formerly RD SNAKE
Mar 5, 2006
5,733
401
How would a bad cat make the cyl dead? I can understand it runnin like shit, but those cylinders should still fire.

The Cylinders are not "dead". They are working like they should. Coils are firing and compression is good. When you have a bad cat, it's the same as a plugged exhaust. If the exhaust cannot escape the cylinder it works as a restriction, a huge one at that. It cannot push the Exhaust gas out fast enough and bogs the engine down. A lot of off road people run into and cars with bad cats lol. I've only seen the problem 3 times. 2 escapes and 1 GTO.
 

wolfe

in black sheep's clothing
Jun 2, 2008
17,632
333
Si Oh Em Pee Tee Oh En
The Cylinders are not "dead". They are working like they should. Coils are firing and compression is good. When you have a bad cat, it's the same as a plugged exhaust. If the exhaust cannot escape the cylinder it works as a restriction, a huge one at that. It cannot push the Exhaust gas out fast enough and bogs the engine down. A lot of off road people run into and cars with bad cats lol. I've only seen the problem 3 times. 2 escapes and 1 GTO.

Ok, that I understand. I was just confused because in the first post he said that cylinders 4 and 6 were dead. So I figured they weren't firing.
 

Flyn

Go ahead. I'll catch up.
Moderator
TCG Premium
Mar 1, 2004
68,052
27,984
Selling homes on the Gulf Coast of Florida
The Cylinders are not "dead". They are working like they should. Coils are firing and compression is good. When you have a bad cat, it's the same as a plugged exhaust. If the exhaust cannot escape the cylinder it works as a restriction, a huge one at that. It cannot push the Exhaust gas out fast enough and bogs the engine down. A lot of off road people run into and cars with bad cats lol. I've only seen the problem 3 times. 2 escapes and 1 GTO.


I was at the Forest Preserves one time with my GF and an old couple were trying to get their car started. It would sputter, run really rough for a second then die. I saw the guy had been backed into a spot by a hill and looked at his exhaust. It was plugged with dirt and clay. I told him to wait a minute and used my knife to cut the stuff out.

Of course he tried to start the car while I was doing this and blew the rest of the junk in my face. Thanks old man. Car ran fine after this and he and his lady friend drove off into the sunset.
 
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