Hi, I have a 2005 Neon SXT and roughly 6 months ago somebody had put sugar in my gas tank and I was having problems. I got it fixed though and the fuel tank sandblasted, new fuel pump put in. After that, my car was running fine until just recently. Now, when I try to start my car (usually in the morning or if the car hasn't been driven in a bit) it will start but then die. Its like it won't idle. I have to press the gas after I turn the key to keep it idling. I keep my foot on the gas for a little while, and sometimes when I let off it will be idling, or sometimes when I let off it will die. When the car is started, it has no problems running. The problem is getting it to stay started at first. There is no check engine light on, so I have no idea how to diagnose this problem. I was reading a different post about a guy with a similar problem, and someone seemed to think it was the idle air control valve (IAC). My dad thinks it might be my fuel injectors. I've heard from other people that it could be my fuel pump. However, I rule out the last one because I hear my fuel pump turn on. Any help you can give me would be appreciated!

Edit: Also, not sure if related or not, but my car is really loud when I start it now. The noise continues when I accelerate at low speeds, as well as when I am idling. The car also vibrates. This has not been going on the same amount of time as issue stated above however (started 3 weeks ago or so).

TL;DR : My car won't stay started (sometimes) unless I hold down the gas until it finally will idle.

 

Have you checked the fuel pressure? That'll tell you if you have a pump problem. If the fuel injectors were bad, I'd think you would have a problem all the time; not just on a cold startup.

Are the plugs and wires good as well? Old/bad wires can cause the car to die too.

 

Just a thought... Check your EGR valve. It could be stuck.

 

The fuel pressure is good, checked it last night. I agree with your idea of the fuel injectors. I replaced the plugs and wires like 4 months ago, so they are fairly new.