Car Stutters and Dies

[Jetglx99]

Hey guys, My girlfriend drives an 01 Focus ZX3 with the Zetec motor. Lately it has been running extremely weird. Sometimes she will be driving and it starts to stutter violently and then shuts off, sometimes it will start back up, sometimes it has to sit for a little and then will start back up. The past few days it has died while warming up, but doesn't die until it has reached operating temperature.

Car has a short RAM intake, and aftermarket muffler. Also has new fuel pump, new sparkplugs, new MAF sensor, new valve cover gasket.

Any suggestions or insight on this problem would be greatly appreciated.

[Sponsor]

[whynotthinkwhynot]

Our first demon to check out is the PCV vacuum line, and of course, the PCV valve itself. I would also recommend cleaning the IACV with spray carb cleaner- use a Q-tip to get all the black out of there that you can. Check and make sure that the plunger is sealing off the 2 chambers. The plunger should be easy to push in with a Q-tip. Any damage to the head of the plunger, or if the plunger is not moving easily- you'll have to replace it.

As far as the PCV goes, the rubber elbow lines are probably collapsing under idle, and that is what is causing your low idle/ stalling. Ford makes a replacement hose that is designed to handle the heat for $20 or so. Check with our vendor Village Ford for a discounted price. I'd give him your VIN, and then tell him what part you need. I'd also order a PCV and grommet from him while you're at it. From what I understand, we're getting the employee discount on parts through them, so I'd order whatever you thought you might want to order from a dealer to save on shipping.

This is just a guess from experience with Zetecs that die out. You should double check and be sure that you have this problem before ordering anything. If you need more help locating the parts in the engine compartment, just ask.

[Jetglx99]

I'll have to check those things out. I'm not used to Fords, I'm a VW guy. I'll let you know if i need any help locating things. Thanks for the quick response.

[whynotthinkwhynot]

IIRC, the PCV is located in the side of the engine block under the intake manifold, and the vacuum line runs from behind the TB to the PCV. I've heard it runs over to the firewall where there is a metal pipe. I haven't worked on a Zetec, so I might be wrong about some of that. Check the VECI for a schematic that will help you locate it.

[Jetglx99]

Last time i started the car, it died once it reached running temperature, like i said before. It wouldn't start again until I took the air filter off the intake and then it started right up and idled fine with no problems. Would switching to a stock airbox fix this problem?