Trouble starting and randomly dying

[ThaGreatOne98]

So, I've been "all around the world" with no one able to assist in solving this issue, so I'm turning to the forum for ideas.

I own a 2007 Grand Prix GXP 5.3L with about 115K miles. I recently had serpentine belt, and plugs & wires changed, as well as the ABS module repaired (big shout out to Cheap-ABS.com!!). Since I had to send the module off for repair, the mechanic went ahead a switched the plugs and wires, as well as replaced the serpentine belt and the car sat for about a week and a half. Got the module back on, and re-flashed. Everything ran well for about two weeks. Well, one day I went out to start the car, and noticed it was having trouble starting. The engine would turn and turn, it would fire a bit, and run a few seconds, and then die. NO CHECK ENGINE LIGHT. I give it a bit of gas peddle while its trying to start, and it'll come alive rough for a few seconds, then idles out fine, with the smell of fuel coming out the A/C vents. Turn it off, and turn it back on, and fires right up, no issues. Drove down the street, and while at the traffic light, it died. Fired right back up and drove on. Took in to the shop. They checked the fuel pump pressure, said it was fine. They eventually said I needed to replace the crankshaft positioning sensor and harness. Got it switched out, and it immediately did the exact same thing as before. Now this morning, it did it, and when it finally began to run, white smoke with a light burn smell came from the A/C vents. Some people say I should change the fuel filter since it sat for a while not running. Others say Mass Airflow Sensor. Others say Ignition Control Module. I just don't have the money to continually replace parts at random. Is there any help for me???

[Fivefingerdeathpunch]

I doubt the crank sensor and harness were even part of the issue, just sounds like a shop shot gunning parts into a car hoping that fixes it.

There is no fuel filter to change on your car anyway, it's part of the fuel pump itself and likely not your problem.

I would atleast remove the MAF sensor and clean it, and clean the throttle body if you can. A bad MAF can cause rough starting issues for sure but I can't say for sure that is the issue.

[ThaGreatOne98]

Ok, so I took it to another mechanic to ask about the MAF and throttle body, and the car actually did the "crazy start" thing in front of him. He said, right out, that it was the fuel pump starting to go bad. He asked me did I feel a hesitation around 40-50mph, and I do. I just attributed it to "random crazy things" this car has always done, so it didn't really send off a red flag to me (I am, by no means, a car expert!). Thoughts???

[rottonj]

It could be the fuel pump, sometimes they die lingering and sometimes its a swift death. Do the MAF and throttle body cleaning yourself as has been suggested, its not expensive and probably needs it anyway. That MAF could also cause hesitation at similar speeds if dirty.