Hi all!

My 1993 2.3l just failed smog due to two issues: 1) Fuel smells and 2) high NOx on low speeds only. Could these be connected in any way?
- I get a 172 code: "HEGO (HO2S) sensor fault/lean". Which makes sense with the high NOx reading, so I do seem to have an engine that's running hot - but apparently mostly at low speeds.
- The car idles pretty rough. Sometimes I feel like it might just stall on me. This could also point to too much air/too little gas under little to low load, right?
- Some fluid has been running down the side of the fuel tank. Its not wet, but it must have been, since there is less dirt around an area that looks like something has been dripping there.

Does anyone have a guess at which components of the fuel system I should check that might be involved in gas dripping around where the filler pipe meets the gas tank? Could these cause cause an issue with the fuel system that makes the engine run lean?

Thanks!

 

Just a quick follow-up: I changed my EGR system (valve and solenoides) and that cleared the 172 code.