My 1984 GSL-SE is running bad once it gets warmed up. Starts fine, but after I drive it for a few minutes it starts misfiring and backfiring when I try to accelerate. I can rev the engine with the clutch in and it will rev ok (some roughness), but as soon as I release the clutch and put a load on the engine it tries to die. I have considered bad gas or a clogged fuel filter. I tried to check the timing and found that is really difficult to see the marks so I am not sure if that could be the problem. Advice needed!

 

Potentially a bad Leading or Trailing Ignitor. Leading in that as it heats up, it builds resistance and stops firing the Leading Coil consistently. Trailing in that it heats up and prevents the Trailing Coil from firing which screws up the trigger for the ECU to know when to fire the Injectors. Search on my name and "SE Ignitors" for more info. Good luck,