Hi guys. My girlfriend has a 95 mazda protege. It is idleing pretty rough but fine at all other engine speeds. I changed the spark plugs but that didn't help. I cleaned the throttle body out and it was pretty dirty and it helped a little but not much.

I'm thinking of doing a full tune up but was wondering if the timing is electronically controlled or if it has a cap and rotor i need to replace and manualy set the timing.

the car has 114K miles

Thanks for the help.

 

Yes, you have to set the timing manually with the help of a timing gun. Other things to consider when experiencing rough idle are:

- Fuel Filter
- PCV Valve
- O2 Sensor
- Air Filter
- Spark Plug Wires

What was the condition of your old spark plugs?

Regards,

Oz

 

I don't remember the condition of the old plugs. I assume the O2 sensor has a maintance schedule right? How much does one of those cost and where can i get it. Its located right after the exhaust manifold correct?

 

The O2 sensor doesn't really have a maintenance schedule. It's like your starter or your alternator. You don't change those unless you experience some failing symptoms.

As far as I know, we only have one (1) O2 sensor located just below the exhaust manifold heat shield attached to the exhaust manifold downpipe/collector. You might get away getting a Bosch Universal O2 sensor which costs around $20-25US. Or get a Direct-fit (probably from Bosch too) around $50US. Shouldn't be too expensive.

Regards,

Oz