240SX Running Rough, Misfiring on Cylinder #1

[nayray]

My 1993 240SX started misfiring last week after a drive up to Portland and back. I eventually took it a shop where they told me the o2 sensor had a code 33 25 key cycles ago, had corrosion in the distributor cap and had a bad #1 fuel injector. I've replaced the distributor cap and rotor, spark plug wires, spark plugs, the fuel injector in cylinder #1, and cleaned the fuel plate and still get a rough idle. If you rev the engine the roughness doesn't exist and if you pull the wire to fuel injector #1 the engine doesn't shake anymore. Any help would be VERY appreciated.
Modified by nayray at 10:25 AM 11/19/2008

[s13_chris]

You check the spark plug gap for #1? Get a volt meter and check each fuel injector power wire and see if they all are getting the same amperage. Check compression for Cylinder #1 also. And if you have time, pull the valve cover and check the (i'm forgetting the name of the part but I'll try to descrive) valve arms. The arms that move up and down that open and close the valves. If any of the arms have movement with your hands then you may have bent valves. Let us know.

[MJDalton]

Wait!!! You said when you pull the plug off of injector one the engine runs normal "so to speak"? That makes no sence unless someone tuned it to run on three cylinders.

Check your wires again. Make sure they are connected properly. Also if you have a timing light chech your timing. Should be 20* BTC

Good Luck

[nayray]

My spark plugs are gaped correctly, the fuel injector wires all seem to be consistent, the spark plug wires are correct, i don't have a timing light so I can't check that but I don't have any reason to assume its changed from when it was running fine. I'm out of ideas and running out of technical ability, I may very well take it back into the shop tomorrow. Let me know if you have any thoughts or ideas. Thanks for the help guys.