1998 LS400 cranking not starting

[goldendorp]

For the past year or so, if I leave the car alone for a few days, regardless of temperature it has trouble starting. When I go to start it it will crank for a while but only fully start by giving it gas. When it starts an large plume of smoke along with fuel smell fills the air. Check engine light is not on.

I removed the air intake plastic stuff and put the key in the on position and a rock on the gas pedal. I removed the plate at the top of the throttle body and sprayed and cleaned out the 9 or so mini holes and the 2 larger holes. With my limited car knowledge I assumed this area to be the air intake bypass when the pictured valve is closed. I cleaned out throttle body as much as I could from the front without removing it. I had good results with this. The car started and maintained higher rpms than before. I thought it was a great success.

I then left it alone for 10 days and it wouldn't start.

What should I check next?
Do oxygen sensors have a role is starting or just running?
Does the MAF sensor have a role in starting if the throttle plate valve is closed during starting? (I didn't mess with the MAF sensor) Air filter is about a year old, lightly dirty, not filthy.

Help... I like this car, but I don't like the Lexus service bill. Thanks.

[Lexus_DK]

Check the health of your battery. Is it supplying the proper cold cranking amps and voltage?

[Lexus_DK]

How often do you pump gas? Maybe gasoline bad, fuel pump or clogged fuel filter.

[sha4000]

How many miles on the car? Check your battery terminals and make sure they are clean and tight. 

[goldendorp]

140,000. Battery was replaced this winter. Terminals are clean. Started right up this morning no problem after running it 2 days ago. No pumping the gas, no smoke. 

[goldendorp]

Unsure about age of fuel filter. 

[sha4000]

If no codes are popping up it might be a sign of the starter getting ready to go. It's just a guess though.

[goldendorp]

Starter replaced 2 years ago. Hmm...