I have a 2003 escalade that will not stay started. i changed the fuel filter and pressure regulator but it still sounds like it isnt getting enough fuel. i can hear the pump turn on and prime the system. every now and than it will start and stay running for about 3 seconds and than die again

souinds like a break in the wire connector to the coils . id randomly check each line every 1 inch with a probe tester and see if the line isnt dead .

Fuel pressure regulator may be vaccuum actuated on forward fuel rail... as this regulates fuel rail pressures, also see if fuel is making it into vacuum line if it is ... diaphragm popped, check this first. Before a fuel pump, which sounds where this is leading...

sounds like a fuel delivery problem, have you had the OBD read ?the backfire could be a symptom of timing out or misfire so need to check a few things

It sounds like your car isn't getting the proper amount of gas. You say your mechanic changed the fuel pump and the regulator. Id have him run a diagnostic tool on it to see if it throws any other codes. Its getting fire. Try changing the FUEL FILTER. it maybe clogged. maybe the pressure regulator is not giving it enough pressure to push the gas into the engine or maybe the fuel pump is only working at times. Does it run good and then start to spit and spudder then die? if so its not getting gas some how. Idk if you can adjust the pressure regulator or not. i mostly work on old school cars.

Well you know one thing, your air, spark, and fuel mixture isnt right at first start up. Sounds like a fuel pressure problem. Your fuel pump may not be hold pressure or fuel regulator on the fuel rail may need to be replaced. Regulators are pressure activated and use springs to regulate gas flow like when you start your car drive and idle. Also check for leaks or cracks in fuel lines as they can cause the same effect

pull the vacum line off your fuel pressure regulator. If it smells gasy or has gas dripping from it, replace the regulator.

SOUNDS LIKE TIMMING CHAIN REPLACEMENT NEEDED

check change the fuel filter and check the vacumn to the fuel pressure regulator also check the fuel lines to make sure one isnt collapsed as well

If the car fired after pouring gas into the engine, then you should check your fuel pump, listen when you turn on the key, if you hear the fuel pump start and stop, then check your fuel pressure, all fuel injected vehicles have fuel pressure regulators, if your fuel pump isnt pushing enough pressure to the regulator the car will not start, and if it does start it wont operate properly, and may even leave you stranded.. If your fuel pressure is low, check the fuel filter, dirty filters restrict pressure, and are ALOT cheeper to replace than a fuel pump!

I have a 2003 Escalade with 114,600 miles on it.... My engine light came on as well. It just a little rough especially when sitting at stop light/sign.... (If your anything like me, my stress level went through the roof.) I took it to Autozone first and a nice young gentleman ran the OBD II Code Scanner for free. The code was 300 which is misfire and it listed possible sources. However, he didn't think the sources were the actual problem and told me to check my fuel filter and fuel pressure regulator..... So I took it to the shop (whom miracously diagnosed it for free, maybe because I told him that I was sure it ws the fuel filter and pressure regulator) He confirmed the problem was the fuel pressure regulator and showed me how it was spitting a bit of gas out everytime I started it (which explained the gas smell I was trying to ignore.)
COSTS:
Fuel Pressure Regulator Parts: $115 Labor: $85
Fuel Filter Parts: ten bucks!!! Labor: three bucks!!!!
Total cost: $224