Purchased a very stock 260z (auto trans, flat tops). Was not getting fuel to carbs so I replaced the mechanical pump, new fuel filter and fixed electric pump. Was getting gas to carbs but car would still not run. Checked compression and got good numbers across the board. Checked timing and discovered it was not showing up on my gun. Turns out the PO had the plug wires in the wrong positions. Corrected that. Car now turns over runs for about 10 seconds and dies out. Decided i'd dump the flat tops and replaced them with some early model round tops. Also removed all the extraneous smog stuff. With the new carbs i'm having a very similar problem. Crank the car over, it starts and runs (poorly) for about 10 seconds. Throttle is totally unresponsive. Any ideas? Thanks!