bryan1354

Hi,
I have a 2001 Honda Civic Hx with 160,000 miles and I am getting a code P0303 Misfire on cylinder #3. When the car is at a stop and idiling the RPM's go low and the car starts shaking and when I turn on the AC the car starts shaking even more and it makes a squeaking noise. Would this be a coil or my time belt causing this problem?

Matt_75

You might want to take a look at your spark plugs. Were they ever changed? If you do decide to replace them, I recommend you use the OEM NGK's as replacements.

The squeaking sound is probably coming for your drive belt that goes around your compressor and alternator. No way of knowing for sure with out listening to the problem.

bryan1354

Spark plugs were changed recently... Would that cause a misfire tough??

Matt_75

It could if it wasn't gaped correctly or installed correctly...e.g. over or under tightened. Or you used after market plugs not meant for the car. In my experience, some cars are picky about having the OEM plug installed because that's what the computer was programmed for.

You could also check the coil pack to make sure it's seated properly as well.

Joeostick

i have the same problem changed the plug and ciol pack and timimg belt any other ideas?

Matt_75

Did you use OEM plugs?

You could have coolant leaking in that cylinder causing the misfire because your head gasket is blown.