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Extremely Bad Missfire And Rough Idle

Chris34

By Chris34,
in General Maintenance

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Chris34 Enthusiast

Chris34

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Posted

Ok so firstly, the problem. Soon as I start the car, it idles fairly smoothly as per normal however you can feel these low-pitched subtle pops/thumps coming out of the exhaust which you can feel while sitting in the car. As I start driving it, the car starts jumping and that low-pitch popping sound becomes consistent with the revs and basically the car barely goes anywhere. I first had it looked at through a workshop and he said it was probably burnt out spark plugs, turns out yes my spark plugs were burnt out so brand new ones were put in.

I picked up the car and the car drove perfect! That was until boost comes in, as soon as boost came in, the same thing happened again (as above). Then for a short period of time on the way home, it was all clear and the car drove perfectly both on and off boost and was as it use to be. But then the problem came back where the missfire and popping/thumping would happen just above 1500rpm. I barely made it home.

Does ANYONE know what the problem is/what's causing it?

Not sure if it's relevant or not, however last week the car overheated due to the plastic spout on top of the stock radiator breaking. I had a new Koyo Aluminium Radiator installed and when I picked it up from that workshop that installed the radiator, that's when this problem occured. However they stated they touched nothing but take out the old radiator and drop in the new one.

lowbro Community Regular

lowbro

Posted
Posted

If your plugs were that old, and it depends how many km's your OEM coil packs have done, I would suggest if you can afford it to replace all 6 x Coil Packs to compliment your new plugs with after market ones (Splitfire, Superspark etc) to save yourself any headaches in the long run. Superspark's are an excellent choice for the price range.

Cefiro RB26 Apprentice

Cefiro RB26

Posted
Posted
Ok so firstly, the problem. Soon as I start the car, it idles fairly smoothly as per normal however you can feel these low-pitched subtle pops/thumps coming out of the exhaust which you can feel while sitting in the car. As I start driving it, the car starts jumping and that low-pitch popping sound becomes consistent with the revs and basically the car barely goes anywhere. I first had it looked at through a workshop and he said it was probably burnt out spark plugs, turns out yes my spark plugs were burnt out so brand new ones were put in.

I picked up the car and the car drove perfect! That was until boost comes in, as soon as boost came in, the same thing happened again (as above). Then for a short period of time on the way home, it was all clear and the car drove perfectly both on and off boost and was as it use to be. But then the problem came back where the missfire and popping/thumping would happen just above 1500rpm. I barely made it home.

Does ANYONE know what the problem is/what's causing it?

Not sure if it's relevant or not, however last week the car overheated due to the plastic spout on top of the stock radiator breaking. I had a new Koyo Aluminium Radiator installed and when I picked it up from that workshop that installed the radiator, that's when this problem occured. However they stated they touched nothing but take out the old radiator and drop in the new one.

Hay i had a very similar problem with my R34 after checking all the above mentioned problems new plugs new coils. i pulled the cas spun the shaft and there it was noisey bearings. pulled it apart marked it carefully pressed on new bearings put it back in bang full power again. no problems even put my old coils back in perfect.

It is actually the fastest check out of all the possible problems and $15 to fix.

neofenrir34 Collaborator

neofenrir34

Posted
Posted

I maybe over doing it here but. You say it overheated? by how much and for how long? these things have alloy heads, i.e. to hot for to long and your head starts to warp (Very bad) Has it used any coolant at all?

might be something to look into

Chris34 Enthusiast

Chris34

Posted
  • Author
Posted

Found out it was the wiring loom/harness for the coilpacks. 2 of the plug clips were cracked so they were basically half in half out sometimes.

In regards to the head being warped...is this something that could be potential in the near future? What's the easiest way to tell?

  • 1 month later...

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