I have a '92 Grand Am that started spitting and sputtering a few weeks ago. The fuel regulator has been replaced. No vacuum lines off, spark plugs are fine, air filter is clean, etc. My friend has a engine analyzer but apparently it isnt telling him anything. Another gear head friend of mine mentioned it might be the catalytic converter being clogged or something. Does anybody else have any bright ideas?? Thanks for your time and input.