[deadchip]

When's the last time you changed the fuel filter? Have you run it super low on fuel recently? Possibly O2 sensor problem also. CEL?

 

[deadchip]

I have had a bad O2 sensor without a code, though it usually does throw one.

 

[deadchip]

PCV valve is super cheap, so you might as well do that anyhow. If it is the O2 sensor, it will get worse. The first time I had a bad O2, it would sorta hesitate at under load sometimes, I think from not getting enough fuel. I also got better and better fuel economy (running lean). It got worse and worse, until it bucked and wouldn't idle. At that point, I unplugged the sensor and the car ran fine in failsafe mode, though this is not a good thing to do for long. Replaced the sensor and it was fine. Do you have any exhaust mods? My EL headers seemed to make thosesensors burn out every year or so