It's ironic, but I have the exact same problem and searched to find an owner's forum...AND this issue was right on top. So, I joined the group!
I have the same problem with a '97 ES300 and it's not going away.
The dealer has replaced the starter and the battery. But after driving along and stopping (say for gas), it will often not restart the first time IF it hasn't been long since it was shut off.
In addition, when I start it normally, the start-up just seems "weak".
Any ideas??
I am having the same problems with a 99 es300 coach edition. The car has spark, but will not ignite. In other words, it will crank but not actuall stay running. The RPM gauge shoots up, and then dies. So, I went and bought a fuel filter tonight. I am going to try and replace this week if I get time. I will let you know what happens.