I have recently brought a 1991 Camaro 305. Ive failed the test twice.I passed the Carbon monoxide.But not the Hydrocarbons or Oxide of Nitrogen.

I git the timing correct, new fuel pump(Needed that),oil filter, fuel filter, and that pollution cloth in air cleaner.

I think it might need a oxygen sensory, or distributor cap and more.

Please help dont want to buy unnecessary parts.

 

Usually "they" will tell you a new cat. converter. But don't waste the money until your sure your egr valve IS working. Mine was having a vacuum leak so it didn't fully work. partstrain, rockauto,partssupply warehouse etc to get one cheap. Not so hard to change on a TBI.

 

What were your numbers and the limits?

 

The actually numbers are
Required Hydrocarbons 0.80 Required NOx is 2.50
My Camaros were 17.46 My Camaro is 3.80