I have a 94z28 that I just did an engine swap and cam and tune in. Finally got done and car won't start unless I press gas pedal nearly to floor. After a few seconds of revving the car finally idles by itself but when I hit the gas again it seems to bog/misfire. Anything about 2,500 rpms it no longer bogs/misses. The tune is from pcm4less and all new plugs wires and opti. Any ideas???

 

Check for a leaky injector.

 

I checked injectors, it's not them. And they ran fine on old setup and the fuel rail never came off the intake during build. Hmmm??

 

Have you tried resetting the IAC position using the procedure on shbox's site?

4th Gen LT1 F-body Tech Articles

 

If you hold the accel pedal to the floor, BEFORE you turn the key to "start", and hold it there until the engine starts, it may indicate a problem with flooding. The pedal on the floor puts the PCM in "clear flood" mode, reducing the addition of fuel during startup. Could be the leaky injectors, could be the coolant temp sensor not telling the PCM the engine is warm, could be a closed IAC valve.