2004 RX-8 Manual, good compression on motor, only 60K on everything. The idle is VERY rough and it sputters so bad when I'm idleing. When I keep the RPMS above 1K with the gas pedal the sputtering/hiccups stops. The sputtering is hard to describe, it's kinda like the noise of it sucking in too much air or air pocket popping, or just a quick dip in RPMS, wish i could give it a better description.

Coils are relatively new and BHR so they are okay, plugs are 5,000 old, i took them out and they look okay, connections are good on the boots. I smoke tested the intake for a vaccum leak, no smoke escaped so that seems fine. IDK what it could be, any ideas? maybe the MAF sensor? When i unplug it things sound a bit better, but it still sputters.

Some of the rough idle is from motor mounts which are going bad, but not sure what the sputtering is from.

 

Clean your MAF sensor.

 

Cleaned it with some MAF cleaner, still sputtering though.

 

Air/fuel/spark are the elements you're looking for. Look at all of the components involved and then look at them again.

Did you check your MAF sensor after you cleaned it to make sure there is no longer any gunk on the bulb or the wires?

 

Do you think I should try new plugs? I got these about 4,000 miles ago. Seafoamed my engine and I guess that really gunked the plugs up, I pulled them out and they were really coated, so i just brushed them with a wire brush.

Coils should be good... they are the BHR ones so I can't see them giving out already after only a few thousand miles.

MAF sensor could be bad too, I made sure there was no gunk on it yep.

 

About the only thing that 'seafoaming' is good for is gunking up plugs. Replace them.

 

Yeah my friend swore by it so I figured i'd give it a try, won't be doing it again. Will do thanks.

 

I proved it does nothing a few years back when used the normal way. Distilled water ingested with the engine running is more effective, cleaner, cheaper, and doesn't foul the plugs.

https://www.rx8club.com/series-i-tec...r-pics-241867/

 

Changed the plugs and it's not sputtering as much, it's just light now so maybe the MAF sensor. WAY better with the plugs changed though, good call guys