Originally Posted by teamlegacy

O2 sensor. When I was running my base map [note: turbo car] it ran 100x better when the check engine light was on throwing the O2 sensor heater code. When it was off, the bitch stumbled and just felt like poop.

Also, make sure you've had a recent tune up. Plugs/wires/cap/rotor/fuel filter.

Originally Posted by PrecisionAuto

Apparently you are not aware that inter gas (such as the exhaust gas flow coming through the egr valve) is not combustible. On that model vehicle the egr ports in the intake manifold tend to clog. When this happens it will leave all of the exhaust gas going to one cylinder instead of distributing across all four. This will cause a miss fire / stumble situation and cause a lack of power. But then if you new more about what an egr does, what functions it serves, and what may happen when parts of the system are not working properly. Then you may have known that. The only reason I mentioned it, is due to the fact that I have had to fix several of these.

Originally Posted by deskjockey

I had the same issue at 4k rpm and it was just plugs and wires for me...