i have a 94 with a diypnp. i swapped out my old plugs for ngk bkr7e copper core. pretty standard on a turbo miata and now my car won't idle. i also put a new set of wires on it also NGK. when i give it a little throttle to keep it running it will pulsate from about 1400 -2000 rpms. All ideas are appreciated.

 

Did you put the plug wires on the correct cylinders?

 

That or vac leak.

 

yes they are on the right cylinders. it could be a vac but i'm not sure how, the only thing that changed was the plugs and wires i'll double check all that when i get home. I will also add that under throttle it is much smoother up to red line with the new plugs. it just won't idle. i was also just thinking that wouldn't it idle high if it had a vacume leak? Mine won't idle at all unless i'm on the gas a little. I did adjust the idle screw with no results.

 

If you switch back to old plugs and wires does it idle fine?

 

Try unplugging and replugging the wires one by one while it's idling. See if removing one or more of the wires doesn't affect the idle or it it affects it ever so slightly compared to the other wires.

 

Be sure to brace your other hand on something grounded to check the insulation on the plug wires..GL



OK edit...i.e. don't touch anything anywhere on the car when you pull plug wires...or you could light yourself up...

A good shock is pretty funny when it happens to someone else, but when you have to do CPR - not so funny...

 

ok so i managed to get it to idle pretty well. i went in to More engine constants and set a target afr of 14.7 now it idles fine. I'm not sure that was the problem but it seems to have fixed it for now.