So, I went to get my smoke test 2 days ago. gas cap test passed. The tailpipe test failed. The HC and CO test failed. My HC WAS LIKE 1550 and the limit here is 220. The CO was a little higher then the limit also. I don't have the results with me so I dont really remember the CO #. I will update this post later on the numbers. Any tips on how to lower these numbers. I don't want to go to a shop and find out what I need to look at to lower the HC and CO. The condition of the car is ok for a 94 ex coupe automatic. It has about 213000 miles. I only had this car for about 2 years. It passed the emission test when I first got it. when it was at around 188000 miles. change my oil every 3000 miles. pretty much stock. only mods is intake and spark plug wires. It recently started to shake when idle. I did some research, I'm guessing I need to change my oxygen sensors, clean my spark plugs and air filter? Please help me out. Thanks.

 

Start with the cheapest and move to the more expensive.

First of all does your oil have a gas smell? If so, you're definitely not getting enough spark or running rich!
You need to also change the dizzy cap and rotor.
I'd also change out the PCV valve. If it's clogged, you'll come close to stalling. If you pinch the pcv valve hose and notice no difference in your rough idle, then your PCV valve is clogged and you need a new one. Get a Honda one at that.

 

First, fill up the Gold/Premium gas, also buy a good gas injector cleaner and pour it into the tank. Drive your car for 2+ days, and see if the smell improved.
Also, when you do a emission test, book a time, and drive you car for like half hour before they start the test. If they park the car there for too long and do the test, most likely it will fail again.

 

sounds like your running rich, check o2 sensor and do basic tune up plugs/cap/rotor/wires and like dpkelly said check your pcv valve

 

also check your sdpark plugs n see how they are burnin, some may be burnin richer than others. an injector may be stayin open too much on that cylinder, i found that to be my prob. when I tested high for my HC on my emission test. Its just an idea!