problem starting

i have a 2000 cavalier, with the 2.2L and an automatic, with just under 85,000 miles.

When it is cold outside and the motor is cold it starts up just fine, but when it is warm out or the motor is warm it has a really hard time starting, i have to hold the gas petal down to get it to start. I have replaces the IAC recently because that was bad, but it did not help at all, i checked for vacuum leaks and found none. I also replaced plugs, wires, and gave it an oil change, and ran fuel injector cleaner through it.

When the motor is finally running it runs rough, you can actually see the motor shaking, and sometimes its only a little sometimes its pretty bad.

Not sure what this might be so any suggestions would be wonderful.

Thanks in advance.

Two things I would be checking, fuel pressure and scan tool data.

I. dont have anything to test pressure, but I can get it and try. There is no check engine light so I didnt think a scan tool would tell me anything.

Just because there is no check engine light does not mean that sensor data won't provide any clues. Sensors can be out of range but still within there acceptable tolerance and never flag a check engine light.

So would autozone be able to tell me anything or would I need to have real time data while it is running?

I would be looking at data. I'm not sure what they are using for scan tools.

Ok, so I tried something out of curiosity. To my understanding if you have the gas pedal floored the car should not start, well I tested this out after work today, and the car started great. Does this mean that I have a leaky fuel injector?

I was also going to test the IAT, CTS, AND TPS. But looking through the manual I rented from the library, it does not tell me anything about testing, it only tells me about replacing, so where do I find what the sensors should be reading at.

Alright, there is the proper amount of fuel pressure. I don't have a scan tool but I took it to autozone and there is no codes at all. I replaced the IAT, and the CTS, but it is still starting hard when it is warm. I am at a,loss now, and I don't really wanna pay the. Garage just to find out what it is.

So any more ideas would be greatly appreciated.

What is the fuel pressure and does it hold pressure?

I'm not sure what it was at I took it to a garage because I don't have the stuff to test it and I don't know anyone that does, but they had it in. There for over half an hour. They said everything checked out.