Probable causes of running lean at idle???

[y87inside]

Ive switched to a tech school now and am enrolled in automotive technolgy. ASE certification baby! Anyways, ive been setting an EGR code 404 i think it is. Well, weve got this badda$$ 5 gas analyzer and we put it in my tailpipe. Well, I didnt get a chance to look at hydrocarbons, nox and all that, but did see that im running an a/f ratio of 19.2 to 1 This puts me a good deal over the stoichemetric ratio (excuse the spelling) of 14.6 to 1. My egr problems shouldnt cause this should it? I mean i could see maybe an increase in hydrocarbons because of higher combustion temps associated with a failed or failing egr valve, but it shouldnt affect my a/f. Any ideas? Im thinking maybe my o2's are shot.

[redbird00]

if the egr code is the only code your setting then thats probably it, i say fix that, then see if your still running lean, its something else, but usually if there is a prob with the 02 sensors, they will set a code...

try some fuel injector cleaner too...

merlin

[ September 04, 2003: Message edited by: redbird00 ]</p>