Last year I took in my 90 Civic w/1.5 for smog and it barely passed. In the last couple months/5000 miles I've replaced the fuel filter, air filter, spark plugs, oxygen sensor, ignition wires, distributor, and PCV valve. The car does consume about half a quart of oil every 500 miles. I've been using Valvoline Maxlife 10w30. Car has about 250K miles. Took it in for smog again and it failed the sniffer. Everything else passed. The smog tech suggested replacing the catalytic converter. Any other tips/advice before I spend $200+ on a new cat? Thanks in advance!