[Guest]

...idling or driving normally? happens whether the motor is hot or cold. After it stalls out, i have to let it sit for about 20 minutes to start ( just turns over but does not start, and if it does start it dies right back out. changed all plugs and wires. O2 sensors were done last summer. have an exhaust leak at the manifold not sure if this could be the cause. Thanks for any help in advance!!!

 

[Guest]

Could be lots of reasons for this, when was the last time you had a service? Obvious things to check are the air filter, fuel filter and the timing. Its possible that the fuel rail pressure regulator needs replacing.
Ja.

 

[Vader]

Check the optispark (distributor). I'm not 100% on the LT1 Impala, but I know they were a problem on the F-body cars.