Very hard to start

Several months ago my 1999 Camry hard a hard start problem when cold (not driven for approximately 8 hours). The dealership could find no problem and suggested new plugs and wires which I decided to do. The problem persisted for several more weeks though it happened less and less and finally stopped. I assumed a bad tank of gas.

The problem has returned big time. The engine turns over but chokes out almost immediately. Multiple tries produce the same result. I had the timing belt the other belts, fuel filter, air filter and battery changed. No joy.

To get the car running it is necessary to "catch" the engine before it stalls by giving it gas, rev to 3000 and the put it into gear. Once the car is driven a little it runs fine. The car has been dealer maintained (every 15,000) with the exception of me doing the oil changes (every 2500 miles with new filter and Castrol 5w-30).

Since the check engine light does not come on (except during the attempts to start the car) the are no codes stored to allow for a code reading.

Any suggestions greatly appreciated.

Thanks

raiderfan