I have an 02 Monte Dale Earnhardt edition an one morning the engine came on for system too lean bank 1.
-replaced air filter an MAF sensor, engine light went off after i cleared the codes
-found vacuum leak from Manifold valve to brake booster an replaced the hose an valve

I still feel like im flying through fuel an my fuel trim was maxed out for a period of time where the computer was making up for the extra air an dumping so much fuel into my trim.
Could it be an 02 sensor without throwing a check engine light? Or could it be my lower intake manifold gasket ?
Its got almost 200xxx miles an i recently did a spark plug change.
It does fight sometimes when it starts but i know it's a common problem with these, wasnt sure if my fuel pump would be related to the consumption of my fuel

 

How does the car seem to shift?? Any abnormalities when driving normally?

 

I definatly need to replace or do work to the transmission eventually because when the fluid gets warm it shifts pretty hard, but i wouldnt think that would do much to the fuel consumption as i started to notice i was flying through gas when the check engine light came on. It sounds like it runs fine and doesnt misfire but i have noticed in the past 2 months of me owning the car i almost went through a whole bottle of coolant

 

Like a full gallon of antifreezeso thats why i assumed it could be lower intake manifoldgasket but i wasnt sure

 

Pull the line from the FPR and see if it's wet with fuel or smells like fuel. Your FPR could have gone bad.

 

i pulled the line off an it wasnt wet at all after driving for 10 minutes also, i started it an plugged the line an didnt sound like any leaks either

 

No, I wasnt suggesting anything rather trying to gather info for myself as I have an ongoing problem I cannot figure out..

It could be the lower intake gasket or the upper.. Or the throttle body.. Or a leak anywhere in the system.. Could be the rad cap went bad and is letting coolant evaporate..

I would assume the two issues are unrelated tho.. My T-stat housing was leaking at one time and never saw any puddles or anything..

Do you monitor anything that isnt displayed on the dash??

EDIT:

Also, the FPR deal.. I dont think you need to actually drive it but rather watch it VERY closely as it idling.. It could take more than ten minutes before it starts spitting gas out.. Thats something you really want to make sure about tho because if it is leaking and you dont catch it, it would give you a nasty backfire that blows the intake manifold up..