Tirones in Nissan Sunny 1990

Hello: My 1990 Nissan Sunny 1.6 is running rough. I replaced the points, spark plugs, condenser, and fuel filter, which was very dirty, but it improved very little. The timing belt was also replaced, the points were adjusted—basically, a tune-up. It was running great until I filled up at a gas station and it started jerking again, so the fuel filter was changed. Almost everything has been checked, and it's still not better. The only thing I haven't removed is the carburetor, since the mechanic says the problem seems to be electrical. I would appreciate it if you could post a diagram showing how to connect a coil that also has a resistor. Thank you for your suggestions.

Hi Gleyton, several years ago I had a Nissan Sunny, the same model as yours, and I had the same problem. I advise you to change the spark plug wires, but don't install the ones from the Nissan Sunny. Buy the ones from a 1992 Nissan Sentra II, and preferably original ones, although aftermarket ones are also quite good. The advantage of these wires is that they cover the spark plug more. Another thing I recommend, and that you tell the mechanic to keep in mind, is that when installing the spark plugs, he should make sure that the spark plug terminal, if it's screw-on, is tightened properly. When the spark plugs are new, this terminal is usually loose, and mechanics don't bother to check the tightness, and if it's loose, there will be jerking. I hope this information is helpful. Bye, and good luck.

It's almost certainly the ignition coil.
I had a 2000 Seat Cordoba and a 2000 Ford Mondeo, and both were jerking after 12 years.
Changing the ignition coil made them run like new again.
Cheers.
PS: Let us know how it goes when you try it.

Dear Antoniorecio: I'll replace the coil and post the results. The thing is, I'd like to see a diagram to guide me on the correct installation of the coil, as it has a kind of capacitor in addition to a resistor, and upon closer inspection, I've noticed that some wires are unconnected. A schematic with drawings of the system would be great. Regarding the wires, I replaced them less than a month ago.
I read online that when tuning a '90 Sunny, there shouldn't be any gap in the diaphragm, but it didn't explain how to fix it. Thanks to everyone who's participating, and as soon as I make the change and figure out how to connect the coil properly, I'll report the results. I'll try to photograph, as soon as the rain stops, which wires are "gone without a purpose" in my beloved '90 Station.

Hi everyone: I wanted to let you know that I bought spark plug wires from Japan, and as soon as I changed them, everything improved, running almost perfectly. As I mentioned before, the old wires were less than two months old. The seller told me that a simple way to tell if the wires were damaged was to check if the radio was crackling or had interference; if so, it was a sure sign that the wires were damaged. Thanks to everyone who was concerned about my '90 gem, and I hope you learn something from my experience. Perhaps the rainy weather in Valdivia damages the wires, or maybe the old ones were simply poor quality. Greetings to all!