Focus problems

The wife is DDing a 2000 focus ZX3. Earlier this evening is started running rough, had a lack of power, and an exhaust the smelled of an overly rich mixture.

We nursed it home and plugged it into our OBDII code reader. Which indicated a misfire on Cylinder #3. I pulled the spark plug and found the gap to be a bit large. I regapped the plug and reinstalled it.

The car still runs rough. I am suspicious of the ignition system, and plan on replacing the plugs and wires. I am considering replacing the coil pack as well they cost about $38...

Still I don't like throwing parts at a problem without having a clear idea as to whats up (I don't mind replacing plugs and wires since they are old and rasty at this point anyways).

Is there anything else I could be overlooking? am I right to be suspicious of the spark plug right off the bat?

Why is it always cylinder #3? Just odd it seems.

Usually when I get this code, the first thing I try is a bottle of injector cleaner.

A 10 year old car without knowing any of the tune-up history would get plugs and wires anyhow.

Bruce

There's a rubber elbow that deteriorates on the Focus and it will cause it to run like crap. Can't remember what code it throws though.

It's a rubber 90 degree elbow that comes off the back of the throttle body (or upper intake manifold) against the fire wall. With the car running, reach your hand back there and feel for it. I bet it's sucking air and causing your rich problem.

Rough running, loss of power, and rich smell are also symptoms of DPFE problems which early Focuses are known for. You might research on Focaljet.com for the easy method to test if it is a DPFE problem. The test consists of plugging the EGR system and will let you know if it is the DPFE very quickly.

DPFE ?

differential pressure something something sensor. it basically senses the flow in the EGR system to make sure its working. very failure prone part, would always throw an egr flow code in the trucks when they would come in.

Thanks guys, I checked the DPFE problem by removing and plugging the vacuum line controlling the EGR valve. It made no difference to the running of the engine. So according to the above linked forum that should not be the problem.

I looked for a deteriorating rubber elbow on the upper part of the intake manifold, I didn't see anything obvious...

• Edit I would think for either of the above issues I would see misfires on a number of cylinders not just #3

I will pick up some plugs and wires on the way home from work today.

In other news I have noticed water leaking into the passenger foot well. during my rummaging around under the hood this morning I removed the plastic tray at the base of the windshield and found a rats nest right on top of the cabin air filter. The dam rats had chewed up the gutter that runs under the windshield so the water could flow right down into the cabin air filter and into the car. I cleaned out the nest and rebuilt the gutter with packing tape, zip ties, and silicone sealant. At least I got something done this morning.

Check the wiring and plug that connects to the ignition coil. (not the spark plug wires, but the voltage source for the coil) They are known for the wire insulation to "shrink back away" from the plug exposing the wires and leading to a premature wire failure.

I hope this helps.

Tony D

Which engine does your Focus have ?
The Zetec does not have EGR.

Slacker update. (yea its been a while...) I removed the coil pack it was cracked in two places. I replaced it and the car runs great!

I need to work on my diagnostics skills I should have been able to identify the problem in about two minutes. Though I am glad to see that my first instincts were right.

@iceracer the car looks like it has an EGR valve, and it certainly has zetec written on the top of the cam covers... (maybe its a California thing?)

Oops. The Zetec in the Focus does have egr. I was thinking ZX2. Which does not.

Try 5-hour energy. I hear it helps you focus.