My 99 Escort ZX2 2.0L DOHC misfires intermittently. I have so far replace the timing belt, coil, wires and plugs. When the car misfires the check engine light comes on and code P0300 is shown. Random misfire. I have once or twice seen the conde for the upper O2 sensor displayed also. Would this cause the car to misfire?

Any ideas would be appreciated!

:banghead:

Here's a quick cut/paste:

A code P0300 may mean that one or more of the following has happened:

* Faulty spark plugs or wires
* Faulty coil (pack)
* Faulty oxygen sensor(s)
* Faulty fuel injector(s)
* Burned exhaust valve
* Faulty catalytic converter(s)
* Stuck/blocked EGR valve / passages
* Faulty camshaft position sensor
* Defective computer

Here's a quick cut/paste:

A code P0300 may mean that one or more of the following has happened:

* Faulty spark plugs or wires
* Faulty coil (pack)
* Faulty oxygen sensor(s)
* Faulty fuel injector(s)
* Burned exhaust valve
* Faulty catalytic converter(s)
* Stuck/blocked EGR valve / passages
* Faulty camshaft position sensor
* Defective computer
Interesting
Ive done the first 2. Going to change the oxygen sensor tomorrow. Would the timing belt have anything to do with this problem?

If the timing was off I would expect all cylinders to be misfiring and the symptoms would be more dramatic.

If the timing was off I would expect all cylinders to be misfiring and the symptoms would be more dramatic.

ok thanks when it doesn't misfire it runs good with lots of power
It might misfire once in 30 minutes