Car is an IS250 2008, up until last friday it was starting fine, then I somehow left the lights on all night and on saturday I became aware of the situation, so I thought it just needed to be jumped, which I tried and it just did not work. The dash board lights up and you can hear crank noises but it just will not start.. asked around on the lexus subreddit and someone thought it might be the gas pressure sensor but then they thought it could be something else since it cranks when i press the break pedal and push the start button.I rely heavily on my car in order to make a living, any help is welcome.

 

Slow cranking from a weak battery is a surefire way to flood a 250. Biggest tip is this. If that battery is near the 4 year mark, replace it. Don't go cheap either.

Depending on how long it's sat between last attempt and next attempt, the spark plugs could be wet (fouled) hence the term flooded.

A couple things to try.
* with new battery, press brake for green light, press start and fully depress throttle and hold it there while cranking and see if it fires off and runs. Try two 6 second attempts.
* starting fluid, remove flex coupler at MAF, spray starting fluid into hose. Reattach w/out clamp, try to start with throttle open like above.
* replace spark plugs. Start as normal.

GL

 

very new to car ownership, what is MAF?

 

it can be starter.

 

Mass Air Flow sensor. It's the wires by the airbox. A fragile component that needs cleaned yearly with specified MAF cleaner.

 

In sunny south Florida that's closer to 3 years especially if you don't park in a covered area and/or only take short trips.