Having problems with your 2000 Ford Focus ?
Car running on 3 cylinders, changed spark plugs but still running rough
Do a compression check. You want to check and see if you have good compression across all cylinders or if you've blown you head gasket or rings. If you don't have any check engine light indicating a faulty crank position sensor, or a misfire on a cylinder, you may have fire on the cylinder but if there is no compression or low compression the vehicle will run roughly. If you need directions for doing the compression check or manually checking the Crank position sensor and other sensors that could cause this condition I recommend the Haynes Repair manual on your vehicle. Most major Auto Parts stores carry both Haynes and Chilton's manuals on vehicle. I prefer Haynes but Chilton's will do as well.
Check the plug wires with a ohm meter, you probably have a bad wire
Repair Help & Product Troubleshooting for 2000 Ford Focus
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