Weird Idle,and didnt pass smog. help?

[BoostWanted]

When i start my car it idles at bout 1100 then drops down to about 800. And when I sit there with it idling sometimes it makes like a puffing sound and you can feel the car shake.

Onto my smog, I failed the hc by about 20 and my no by about 300. Maybe I have a vacuum leak? How do i check? Sorry for not exact numbers. I dony have my smog paper right now.

Also another thing is when I'm driving and I put the car in neutral to coast to a light or something it stays at about 1100rpm until I come to a complete stop.

[Edwin562]

Sounds like a vacuum leak. let your car on for a bit (at idle), spray some carb clean on possbile vacuum leak areas. if idle changes then yes you have a vacuum leak.

[BoostWanted]

Would that fix smog too?

[Edwin562]

No, that will help you find the vacuum leak if you have one. High HC(Hydrocarbon) mostly indicates your burning too much fuel or oil.

[BoostWanted]

How can I fix that? I ran 91 with denaturated alcohol for the smog.

[Edwin562]

Post info on your car.

[BoostWanted]

its a 95 S14. Has like 235k on the chassis and the last owner said the rebuilt engine has 90k on it. Uhh.. what else do you want to know? 5 speed..