From: tremark5 on
In need of assistance my 351 has very high emission readings on hc
and co nox is good have changed temp snsor and o2 sensor run the scan
and it reports code 173 running rich bank 1 does anyone know what
will cause this to run rich it is port injected new plugs and wires
complete tune up has been done ,the o2 snesor is located before the
cat need some direction thanks to all who help toby

From: theshoppabr on
On Mar 8, 5:18 pm, trema...(a)sbcglobal.net wrote:
> In need of assistance my 351 has very high emission readings on hc
> and co nox is good have changed temp snsor and o2 sensor run the scan
> and it reports code 173 running rich bank 1 does anyone know what
> will cause this to run rich it is port injected new plugs and wires
> complete tune up has been done ,the o2 snesor is located before the
> cat need some direction thanks to all who help toby

Check for vacum leaks or a vacum hose off also make sure spark plug
wires are making contact on the exaust mainfold then run a fuel
treatment to clean out the banks high octane fuel usually does the
trick but you can also use alcohol, make sure you run, drive it for a
couple of days before you emission it. If that doesn't work you are
going to have to change that cat. Good luck.