88 Festiva won't pass emissions, where should I start?

[Tuff]

Nice forum folks, thanks for adding me.
This Festiva that I was fortunate enough to purchase from an auction has been a fun little project.
I've done the Aspire suspension/hub swap, off-road tires, new stereo, and a tune-up. I rolled it in for an emissions test and it scores to high on the hydrocarbons. I'm wondering where I should start. The high pressure when I removed the fuel cap has got me thinking EVAP system is plugged.
This is my first Festiva so I'm very grateful for any help that's offered.

[Dragonhealer]

High hydrocarbons is miss fires or incomplete burn. Double check ignition items.
Very high pressure in fuel tank is almost always clogged steel pipe carbon canister to fuel tank.

[bravekozak]

Vent your gas cap. Or see if you can pass emissions with your gas cap on loosely. When you can blow with your mouth from inside out on the cap, it's good.
Then you can throw out all of the evap system, like this:

[WmWatt]

You emissions centre might have a handout on where to start. Ours do here in Ontario.

If you suspect missfires they will sho wup on a vacuum guage or tachometer as a vibrating needle. You mentioned doing a tune-up so presumable the spark plugs are cleaned and gapped. I'd also wipe down the ingition wires and cleamn teh ends and crimp if loose. Also wipe down the distributor cap.

The engine might need a chemcial clean out.

Too much carbon can also be the oxygen sensor or catalytic converter or both but as they cost money I'd only replace if nothing else works. The oxygen senor can be tested with a volt meter. Oxygen senors can also be removed and have the deposits burned off with a propane torch (I've done his on a Honda). That could be cheaper than replacing with new.

Good luck.

[Dragonhealer]

Vent your gas cap. Or see if you can pass emissions with your gas cap on loosely. When you can blow with your mouth from inside out on the cap, it's good.
Then you can throw out all of the evap system, like this:

If you live in an emissions compliance area, all this equipment has to be installed and function.

[Tuff]

I'm going to try driving around without the gas cap for awhile and see what happens.

[Tuff]

I've also got a full tank of 91 Octane with a can of Seafoam additive. I replaced the cap, rotor, plugs and wires last week but that didn't seem to change anything and it still won't pass.