Car battery was dead, got a new battery from Walmart and replaced.

after that, from time to time, the engine would not start when pushing the start button, sometimes it takes 2 or 3 tries to get the engine to start. This has never happened before.

wonder if anyone happen to know the reason for it, could it be that the walmart battery is not as powerful as the previous LEXUS battery? or something else?

by the way the car is due for an engine oil change with the warning light on. I use Mobile 1 fully synthetic 0w20 and the light went on every 5000 miles.

Thanks a lot.

 

Try this, disconnect the battery cables and with a fine grit sandpaper sand the inside of the battery cables. Even if they don't appear dirty, sometimes a thin film can form and prevent a solid connection with the battery posts.

 

thanks a lot for the advice, will try

 

Did you purchase a battery with equal or greater CCA's?

 

In addition to the good suggestions above, I wonder if there might be an issue with your Start switch. If I am reading your description of the problem correctly, it sounds similar to a known issue (mainly for 2007-08 models, though), where a defect in this switch made it hard to start the car.

You have an '09 I realize, but if the battery-related fixes do not work, this might be worth looking into. It would not be the first time that a known problem that's assumed to be isolated to certain model years finds its way to other model years.