Q: Won't start without holding gas pedal to floor, stalls @ intersections

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Car all of a sudden stalled at intersection. Car starts only when pressing pedal to the floor, runs like crap until idle gets up...then seems to run/drive fine. Replaced idle air control valve. Replaced spark plugs. Bought 1-new cool pack, out of the 3 the car has and individually replaced it with no luck. Cleaned/checked Mass air flow sensor. Removed EGR valve, no visible signs although it wasn't like most GM EGR's I'm familiar with as there was really nothing that could be cleaned. Car is dumping black soot/carbon out the exhaust. My next thought is test/clean fuel injectors under intake plenum? Please help!

My car has 140 miles.
My car has an automatic transmission.

Hi there. As you already know, replacing parts without diagnoses can be expensive and time consuming without resolution. The most likely cause for the symptoms you have described is a faulty fuel pressure regulator. Removing the vacuum line to the fuel pressure regulator and turning the key to the on position, without starting, should initialize the fuel pump for two seconds. Fuel will be present at the vacuum nipple, if the regulator diaphragm has split. I recommend having your vehicle’s black soot from the exhaust be diagnosed and repaired by a certified technician, such as one from YourMechanic.

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