running super lean! why

[jesse0880]

pretty much after my rebuild of my 91t, i'v only used half a tank of gas and the spark plugs are purly white already. will it run lean if there is a problem with the ignition cause i susspect the distributor rotor arm to need to be replaced ( i think this cause its the only ignition component i havn't replaced yet). Or is it possable to run lean if my exaust is to restrictive? i think this cause when i had the exaust in my garage during the rebuild, i believe mice were living in it! I think its either one of these two cause i'v checked everything else in the book. please help!

[toyomoho]

Not sure a bad rotor would cause a lean condition, perhaps engine missing. A plugged exhaust can be checked using a vacuum gage connected to the intake manifold. A Google search will tell what to look for in gage indications.

Any gray color with the white, are the plugs still in good condition?

[jesse0880]

the plugs look good except for being completely white... like there isnt any signs of metal flakes and fragments on them. there were brand new NGK's at the begging of that tank of gas.