1999 Pontiac Firebird Stalling

Ok I don't think it has much to do with putting gas in the car. Does it do this any other time? I am thinking that maybe the time it sits as you get fuel that it cools just enough that the coolant temp sensor is not reading correctly and could be causing this. Also do you smell any fuel like a leak? Also you could put some Seafoam in the tank to see if it may just need some cleaning. Get back to me.

Ok no Autozone's idea don't make any sense as the there is no fuel level sensor. There is a sending unit but it don't talk to the computer on the gas guage. I will be asking some questions to try to help figure this out so bear with me. As for the coolant sensor that is correct that is why I asked if it does it any other time. Now I do have another question what does the oil pressure do? What I mean is when you start it does the oil pressure come up and when it does, does it stay up or drop just before it dies? Does it start right back up or does it need a minute or two before it will start again? Do you have the means to check the fuel pressure? If so then you could hook up the fuel pressure tester and go get gas and see what the fuel pressure does as you turn the key on and as you start it and when it dies. Get back to me with what you know and what you can do and we will take it from there.

OK that tells me that the oil pressure sender is working ok so now I would like to know what the fuel pressure is doing when it stalls. I have never had a car do this before in all my time wrenchin so bear with me we will figure this out. I would like to know when the last was the last time you replaced the fuel filter? I also would like to know if there are any performance mods and if so what? The more info you can give the better I can help. Also when it starts back up do you get any black smoke out the tailpipe?

Ok that will work. I would replace the fuel filter however so you know when it was done last. GM has a very tight media with there fuel filters so I recommend once a year replacement. I have done all kinds of performance mods on my car. I also enjoy racing. Anyway just something on the lite side thats all. Get back to me with what you find. Don't spend a lot on a tester you only need one that will do your car so more the 50 bucks is pushing it.

Ok sound good maybe you should get gas before buying a fuel pressure tester? As for the battery have it tested it may be weak and able to hold a load better to check now then to find out when it gets cold one night and you can't start it the next morning. Let me know how it goes.

Ok well now we need to know what the fuel pressure is doing when this happens. It may be that it isn't building up fuel pressure or holding it. I would find it strange to be a fuel pump but can't rule it out yet. So what you need to do is hook up the fuel pressure guage and let me know what it is before you turn the key on and what it is when you turn the key on and what it does as you crank it. Also if you can let me know what it is as it is running too.

Check the oil too. This looks like there is oil in the antifreeze and I am hoping that there is no antifreeze in the oil. Include a pic of the engine oil dip stick too please. Thanks.

Yes it should have had some pressure so I would agree with the fuel pump suspitions. Now as for the engine coolant did you mix red with green antifreeze? If so then you you will need to clean and drain and refill I would use green antifreeze once it is flushed. Now I would also like to know if this is an auto or stick? If auto check transmission fluid too. If the oil doesn't look like chocolate milk then no worries there.

Ok I would say everything looks good except the antifreeze. I would flush it and change it, it looks like it needs it as it looks like someone has mixed antifreeze colors and I would use the green. This isn't related to you running problem I still think that fuel pressure needs to be checked as I am leaning toward the fuel pump on that problem. On the transmisson fluid is that more orange then pink? Hard to tell in the pic. If it is more orange then it is due to be changed too. Let me know how it goes with the fuel pressure check.

Well it could be. I have seen gas cause many problems if it is bad. Never thought Chevron would be one of them. I use Chevron in my baby 98 Mustang so maybe I should change to Shell to see if it runs any different. I am not have any problems but if there gas isn't top notch then it time to make a change. I should have asked if you tried a different gas station sorry. I would also like to recommend putting a can of seafoam into the gas next fill it is an great cleaner. If you been getting bad gas it will help with cleaning things up. Let me know how it goes.