Hey guys, wondering on your thoughts of this:

98 ex, bone stock d16y8, never seen it throw a cel, it's always been in pretty good shape. Anywho earlier today I decided to run a compression test, just to see how things were. I've been a little skeptical with the engine lately, on some days it seems like it really just doesn't want to move, think Geo Metro here.

So I pull the fuel pump fuse and start taking the plugs out, NGK only about 5k miles on them if that, just changed the oil and oil pan 2 days ago (had a small crack), and notice that these plugs are pretty damn black. I show my neighbor who has been doing car work for 40 years or so, he agrees something is up. I proceed with the compression test, letting it crank 5 times each. 190-195-185-200, looking good from what I understand at least.

So, I start to wonder why the plugs are so bad. I clean them off with an air hose, put a little anti seize on them and get everything back up and running. I burn maybe a half quart of oil every 3000 miles, so that isn't going quickly at least. I have been getting worse gas mileage lately, not a huge jump but noticeable for me, about 30mpg even, used to be closer to 35 or more, haven't been using the AC any more or less then I ever used to.

What I'm thinking is that perhaps my O2 sensors are starting to go? Or perhaps my PCV valve, which I've never replaced and could very easily be clogged. What do you guys think?

 

Bump, anyone?

 

how many miles on the car?

The sluggish symptoms and loss of mpg are definitely symtoms of an O2 sensor crapping out.

If you want to check the PCV valve, while the car is running pinch the hose....it should start rattling/making a noise, if it doesn't its not working.

 

I'll take a look at the PCV line when I leave work. Is it often for an O2 to **** out without throwing a CEL?

135k miles by the way, can't believe I forgot to mention that.

 

Alright well it looks like the pcv needs to be replaced, I'll do that tomorrow. Anyone else think it could possibly be an o2 sensor without a cel?

 

You can check your 02 sensor with a multi meter, I'm sure someone can chime in with the proper voltages. I know its supposed to be between 0 and 1 volts.

And yes, your 02 sensor will start to crap out before its bad enough to throw a CEL.

 

Alrighty, am I checking the voltage it's grabbing during idle?

 

just a suggestion i would clean out your iacv(idle air control vlave) and get a new fuel filter.If your doin a mini tune up anyways why not?Just my thoughts