I have a 1996 lexus es 300. code P0303. I have 125# of compression in it. I did the screwdriver to the ear test with th injectors and #3 in the back is not clicking very loud like all the others. Come to think.. the plug didn't smell like gas. What should the compressions be in lbs's?

google the codes you have posted here
codes P0303 and P0302 lexus 300
these are cylinder misfire codes. There is a procedure for this but I would suggest you rad that and follow directions before going the compression test route. The other thing you said was that all this started when you ran out of fuel. Could be you burned out the fuel pump or the pump sucked the junk up off the bottom of the tank and is now plugged up. So many choices but if it was me, I would start with the fuel pump before I started tearing into the motor.

Hope this helps.

Well, an engine needs 3 things to run....fuel, spark, and compression. But they also have to happen in the right time in the right amounts. If you are sure that you have fuel getting into the engine, and you are sure that you have spark at the plugs. I think I would be checking the timing and the compression. And remember, just because you have fuel pressure at the fuel rail doesn't nesissarily mean that the injectors are opening.

Could be the fuel injector on that cylinder.

if you look at diagram below on top of tank it shows a line going to evap that would mean its located behind or next to fuel tank its a some what rounded canister about 8in long and 5 in wide .black plastic.

Cylinders 1-3-5 are on the back of the engine Cylinders 2-4-6 are on the front of the engine. The firing order is 1-2-3-4-5-6 the distributor rotates counter clockwise. Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Plugs...are cheap! Try that First.

The minimum compression required is 95 psi, below this there is no good combustion, incusive the spark plug gets wet in gasoline
If this condition exists, you should check the piston rings and cylinder surface

Buy a hayes or chilton manual for a camry in the same year range. the car is mechaniclly identical and will cover motor mount replacement.

If you have coils and spark plugs then you don't have wires. From personal experience these car's misfire because of coils and BAD INJECTORS. If you replaces coils and sparks plugs you need to check injectors. Get a NOID light and check injectors pulse to make sure it good. First you must locate the cylinder that has the misfire/Missing,this can be done by using a computer/code scanner or if can be manually by disconnecting each coil and see when there is NO change in idling or shaking. What you are looking for is when you disconnect the Eugine should shake more and when you reconnect it would smooth en out. If any cylinder when disconnected the engine doesn't change that the one with the problem. Check again for spark and make sure it good. Then check that injector pulse plug off injector connector and connect it to NOID light you should get a constant flickering of NOID LIGHT. If you do then BINGO that injector is BAD. However I must say this test is on valued if you have performed a compression test on all cylinders to make sure there are no BAD/Burnted valves. This can be done with a compression guage remember the reading should NOT be more than 10PSI difference between all cylinders example of a normal reading is cylinder 1 170 psi cylinder 2 168 cylinder 3 172..... abnormal is cylinder 1 170 cylinder 2 85 cylinder 3 172 ...etc. I know this is alot of info but read through and follow these step and you'll be ASE certified by the end of this job. Good luck and thanks for using FIX YA

Quite often that is to do with your Gear Position Neutral Safety switch.