Misfire low rpm

[K100J]

Hello,

I have a 2000 rx7 fd3 with a recently rebuilt engine.
It has a misfire at idle and runs rough, but does not cut out. Revs perfectly through the range and does not stumble under load. Plenty of power.
The engine has just been run in at 450miles.
I’m about to pull the plugs and check the leads and coils this week.
Any common issues to be aware of?

There is also a loud rattlesnake type noise from the turbo area on over run? Sounds like a wastegate arm? Not sure if this is Normal. Turbos have been refurbished

John

 

[rob fd]

What rpm is it idling at when up to temp? The plugs foul up a bit when just pottering around my idle improved massively after plug change and adjustment of the idle screw. I can't see it been leads or coils if it pulls well through the revs but i'm no expert so don't take my word for it. Rattle noise is potentially turbo heat shield? Mine has started rattling a bit, its driving me nuts lol.

 

[K100J]

What rpm is it idling at when up to temp? The plugs foul up a bit when just pottering around my idle improved massively after plug change and adjustment of the idle screw. I can't see it been leads or coils if it pulls well through the revs but i'm no expert so don't take my word for it. Rattle noise is potentially turbo heat shield? Mine has started rattling a bit, its driving me nuts lol.

Thanks for the reply mate, it’s idling about 800-900rpm when hot. It’s almost like it’s just one plug as it isn’t a horrendous miss.
I think it might be the cat that’s rattling unfortunately.
I’ll pull the plugs tonight. Are there specific plugs anyone uses on here?

 

[rob fd]

Use NGk BUR9EQP in all 4.

 

[K100J]

Use NGk BUR9EQP in all 4.

thanks bro!

 

[Paulm]

Mine did similar, was vac leak

 

[K100J]

Mine did similar, was vac leak

Interesting, she’s behaving since I cleaned the plugs tonight. Still gives the odd pop here and there but otherwise sweet.

 

[Paulm]

Interesting, she’s behaving since I cleaned the plugs tonight. Still gives the odd pop here and there but otherwise sweet.

Good news, mine was caused by the car being assembled by an imbecile.

 

[K100J]

Good news, mine was caused by the car being assembled by an imbecile.

Oh god that sucks mate. I take it the odd miss here and there is normal operation? It’s hardly doing it at all now

 

[rob fd]

Oh god that sucks mate. I take it the odd miss here and there is normal operation? It’s hardly doing it at all now

I think a lot of them do it. I wouldn't be worried if it drives and boosts well.

 

[Paulm]

Oh god that sucks mate. I take it the odd miss here and there is normal operation? It’s hardly doing it at all now

It improved a lot after i found the breather on the oil filler was broken off. Then when i sorted out the problem with the bov not working, ie the vac pipe from inlet manifold was connect to fresh air, not the actuator. It settled right down

 

[K100J]

It improved a lot after i found the breather on the oil filler was broken off. Then when i sorted out the problem with the bov not working, ie the vac pipe from inlet manifold was connect to fresh air, not the actuator. It settled right down

Wow.. I’m tempted to smoke test mine at work tbh. Might be a small leak somewhere