I have an 87 GXL.

Problem: It idles rough... not to the point of shaking things up but just enough to miss a beat frequently. I hooked up a timing light to check the timing and it was fine. Upon checking my timing I noticed that every time the car would miss fire, the light would go off (I know... duh!). The light was clamped onto L1. Could the problem be fixed by simply changing my plug wires?

If so then what wires would you recommend? I can't spend $200 on wires but I want anything from 8-10mm wires to put on there. But I will replace them only if new wires will fix the misfire.

My 7 has 95K miles and I don't think the wires have been replaced before. Also, do the coils go bad frequently and if so then is a bad coil distinguishable from bad plug wires?

Any suggestions on how to further diagnose the problem would be very helpful!

A lot of questions and I appreciate the response.

Thank you very much!!

 

Buy new wires. But, if you put the lite on the rear rotors lead plug, do you still get the blink? If not you might try putting one of the good (if you have one) trail wires in the place of the blinking wire and see what happens. Just a game. Replace the wires. Magnecor. See http://www.mazdatrix.com/ign-3.htm

 

Thanks for your response and I will give your idea a try! I never thought of changing the wires around.

Which wires do you recommend as replacements?

So in order to distinguish a bad coil I have to try the wire thing first? If wires don't fix then I need new coils... correct?

 

Try this site http://www.teamfc3s.org/main.shtml it has an article on wires. I would'nt over trouble shoot it. Just buy the new wires and see what happens. Doubt if it is the coil. The lead wires share the same coil. There are two coils for the trail plugs. The leads fire at the same time from the same coil. Car will run without the leads hooked up and vicey versa with the trails. Leads are the important ones. Now for the deep dark secret...i am using pep boys wires right now. Don't tell anyone.

 

I had this EXACT problem about 7-8 months ago. It when it "misfired" both the leading AND trailing coils seemed to not fire, so I ruled out a coil going bad. Also, I had new spark plug wires. The problem just went away one day, I don't know what else to say.

 

Hailers,

Your secret is safe with me!!