If it runs better when you rev the engine, that suggest a fuel related issue and not ignition.
Check the fuel pressure regulator by removing the vacuum hose and checking for fuel. If there's any, then that's your problem.
If not, it may be a sensor (not 02) that's intermittent. Sometimes they won't produce a code until they fail enough for the computer to detect it. You'll need a better scanner that's capable of reading live sensor data. If you aren't knowledgeable in that area, you'll have to get a tech to do it.
Tuesday, November 23rd, 2010 AT 7:01 PM