89 Buick Century failed emissions test for HC and CO, could fuel filter be the problem?

I've tuned up my 89 Buick Century with my mechanic neighbor, changing the oil and oil filter, replacing spark plugs and plug wires. I haven't replaced the fuel filter yet so could that be the reason it's failing HC and CO levels? I only drove it for 15 minutes before idling in the test station driveway- should i have warmed it up longer?

HC Standard: 220. 1st idle 372. 2nd idle 313.
CO Standard: 1. 1st idle 1.338. 2nd idle 1.0655

CO2 is around 13.

Thanks for any help!
 
Back
Top