So this is very helpful stuff but now i need help with a solution. I have a stock 90 civic si and I bought it with a crap intake on it that had duct tape and non sealed connections to the throttle body and the filter. I got a new hose connector and after i fixed it my car now idles at like 100rpm until it stalls out. I get a strong fuel smell and my ecu is showing a 3 code and a 5 code. It ran fine before i fixed the intake. Pls help.

 

is your vacuum line to the throttle body from the MAP sensor connected?

 

Everything looks to be as it should. I will check it all again in the day light though. Is it possible that my IACV is dirty and clogged enough to effect it? It runs fine above 1k rpm but wont idle at all. Let me know if this belongs in a different thread. Im new to the forum and haven't touched a Honda since my last EF Si more than 10 years ago. PROBLEM SOLVED. Turns out that looking for issues is waaaaay easier. The small t shaped vacuum hose from the throttle body to the MAP was unplugged but looked attached until I pulled on it. Works fine now and fixed my low idle too.