engine miss

[kglowacky]

My LS1 swap has been great running for around 5 years. Yesterday I took it for a ride, and it developed a miss on acceleration and at all speeds. Got my mechanic coming by to place on a computer. The gas is probably 6 months old. Thinking of adding a additive the see if it is bad gas. Any suggestions on a additive? My guess is coil. donor car was a 2002 Firebird trans am

[Willie Makeit]

i'd bet a dollar to a donut if the fuel is that old it has a stuck injector. a quick ODB2 scan will tell you whether it's ignition or fuel related

[kglowacky]

Thats why I am thinking an additive may unstick it. Thats what I get for not driving it more.

[Accelo]

It's all speculation until you scan the computer.
An additive is unlikely to work unless the injector works partially, as it will never reach the injector.
Let us know what the scan identifies.
The self-diagnosis is way better than the earlier cars.

[leegreen]

perhaps loose plug wire or bad connection on a coil pack or injector.....with a seldom used vehicle, make sure mice have not been eating and peeing on your wires