Misfire 3

Hi-this is my first post. I have an 04' Hyundai Elantra. Starting running really rough and chugging around 40-45 miles an hour. When it comes to a stop it acts like it could die. Changed spark plugs and it ran fine for about 2-2 1/2 weeks. After the next time we changed the spark plug wires and that was about almost 2 months ago. Now it is back and running so terrible. Anybody have this issue or can tell me what to try next.

 

Do you have a scanner to watch data pids?

Do you know how to check for sparks? Extend distance to see quality of sparks?

Check for vacuum leaks?

Check injectors?

 

We have checked the sparks and everything seemed to be working. We will be checking the injectors next. I am just not sure why when we replaced the plugs it ran fine for the little while and then when we replaced the wires it has worked for almost two months??

 

Scan ECU and see if there are any trouble codes.
If you suspect mis-fire then do an engine balance test to see which cylinder isn't contributing.