I need help with my 1996 Monte Carlo z34. I noticed that the check engine light is flashing and the engine is shaking violently but i put new spark plugs and wires with a new battery and alternator. The code that pops up when i took it to auto zone says fuel injectors are bad but they are new along with the spark plugs and wires. What should i do.?

 

did you by chance take the upper intake off to get to the back 3 plugs

 

Make sure the plug wires are on the correct plugs and that they have seated properly.
also you may want to change the Fuel filter, looks like a small beer can under the passengers side of the car almost under the seat, but in the Chassis of course.
It will come around with some adjusting