failed emissions '91

[lolon00b]

I bought a '91 4runner a few months ago. It failed emissions yesterday. These were the results:

High Speed CO: 2.52% (1.2% allowed)
High Speed HC: 241 (221 ppm allowed)

My runner is a 6 cyl, EFI, with 226000 miles.

Does anyone know what causes these numbers to be so high? I have been doing some reading and am thinking it may be the o2 sensor? Help?

 

[Acidmeld]

Check your plugs and wires. Your not completely burning the fuel.
Where are you that they still test 91s. Even chicago with their iron fisted emission regs dont test pre-obd2.

 

[lolon00b]

I'm in Las Vegas. Thank you, I'll check those.