Engine running badly - misfiring.

[TheBlackMoth]

Recently the engine in my MX3 has been getting worse and worse and after a 300 mile drive on the weekend it is misfiring/spluttering all the time and sounds like an impreza!

Before the weekend, the car was running absolutely fine when cold, but as soon as I'd been driving for a five mins and the engine warmed up it started misfiring up to about 3000 revs.

But I only did a short journey to work and back everyday, so it didn't seem to get any worse, but after my 300 mile trip on the weekend it really doesnt sound right - it is misfiring throughout the rev-range now and the idle at 600rpm is very unstable.

I have checked the plugs and they seem ok, although the leads were a bit loose and oily...

Does anyone have any ideas on this?! It seemed to start as the weather turned crappy, so i thought it might have something to do with the damp..?

[mx3boyze]

Basic Tune up, Get New plugs, Plug Wires, Distributor cap and rotor button. If its still happening look into checking out the distributor itself.

[Mazdaspeed96743]

Guarantee its the distributor, happened to my RS before..

[TheBlackMoth]

cheers mazdaspeed, how can I check it? Will I need to get a new one if this is the problem?

[colinf004]

if you did an engine swap, remember gotta change the ECU as well. I didn't at first.

[thebonestockkid]

Guarantee its the distributor, happened to my RS before..

Co-sign. Same thing happened to my old DE, although it was a slow progression where the engine would die while driving. Wait a few mins and started back up again.

[TheBlackMoth]

Cool, so where do I go from here? Do I just get a new dizzy or is there a way I can test/fix it?

Cheers guys!

[xSocialx]

Well before you go do all that stuff, check your spark plugs, make sure the electrode still has some length to it. My GS had the same problem put new spark plugs in the other day tested for compression and all is well. Just my 2 cents

[TheBlackMoth]

Yeah, ive checked the front plugs and they're fine, I don't have the right socket to chekc the back ones, but don't see why they'd be more worn..!

The leads are a bit loose, but pretty sure thats not it...

[msd-supermx3]

check everything from spark plugs to distrubitor wires. Check the cap and the rotor, and the coil (have to take apart the disty) if its bad, try to do the HEI mod. Helped me

You can find all the info around. Just look for HEI mod. lol

[Mad Cow]

New wires and disty cap helped mine out alot. I would start with those and then work your way to the disty and coil.