Running pig rich?

[Hoffman Anthony J A1C 552 CMS/MXMVC]

Matt,

Any other theories?  Could it be the thermotime switch is faulty and my cold
start injector is firing all the time?  I reasoned out the O2 sensor, since
it still runs really rich at WOT and idle, two conditions in which the
computer is in open loop and doesn't receive O2 sensor input.

When I got the car it didn't have an air filter (a dubious "performance
enhancement" by the previous owner), so I installed one right away.  Could
it be that the air metering plate is sticking open occasionally at idle from
gunk buildup and causing the rich condition?  Any BTDTs would be most
helpful.


>>>>Never seen that, the fuel pressure is such that it would be pretty hard
for the plate to stick up.

>>>>Did it run poorly before the fuel tank switch? If not check the new
things you changed - specifically the fuel return lines for pinch/kinks or
crud in the return in >>>>the new tank. Did you seal the inside of the new
tank? If so, see if you plugged the return. 
>>>>Also, check the cold start valve, could be stuck open. You can unplug
it, but if it is mechanically stuck upen (most usual) you will have to cut
its fuel supply.

Tony Hoffman