I am in the process of making a 1977 Nissan 280z road worthy once again after having it sit for about a year. Here's what I've done:
- cleaned fuel injectors
- cleaned fuel lines
- replaced air filter(high flow)
- Pressure tested fuel pump
- Passed emissions
But for some reason, once I've run the car for a bit and warmed it up, the engine starts misfiring badly. It's about at 50% of the time when acceleration on first gear; I press the accelerator and it starts stuttering, and the rpm gauge jumps around wildly. The only way past it is to either stop wait for it to pass, or press the accelerator lightly and "ride it out" all the while having it misfire. Once I'm able to get past this episode it runs fine until I start hitting higher RPMs at 3rd and 4th gear. I can't go any faster than 50mph on the freeway, as the same thing happens as on 1st gear, but it always happens.
Doing some research has led me to believe it may be either the EGR valve, or the Ignition Coil, both of which I believe are stock.
Thank you in advance