I have been driving around with my long tube headers for a few months and figured I was running pig rich. So I got myself a MAFT and hooked up AutoTap.

AutoTap is telling me that my average LTFT's are approx 6. Doesn't this mean I am running lean? How can that be with headers?

Confused....

 

Sounds like you have a header leak. Odds are that there is air escaping before the 02, the 02 is reading lean and dumping a ton of fuel in.

 

I have everything welded up. Except to the engine block of course. Could this be where the leak is? I've heard of header bolts coming loose but shouldn't there be some sort of noise if I have a leak?

 

There is usually a ticking sound with exhaust leaks but maybe your the oddball that didn't get the noise. Just look over it and check all the bolts. Since these cars are such a p.i.t.a. you can rub your finger around the flange and see if any exhaust reminants appear. Not the best way but if its bad you'll have a very dark finger.(unless its oil of course)