Stutter at 3800rpm even after new coils and grounds
 

Please help guys!

I own a 2004 rx8 with the australia Mazfix turbo kit on it. It has also been flashed by them, has bigger exhaust racing cat etc..

Ever since I have owned it for the past six months it has had a hesitation at 3800rpm under load when in gear. Under throttle it will stumble then pick up past 4000rpm.

Knowing the most likely culprit was coils I updated and installed the BHR coil kit with new spark plugs and leads as supplied by BHR.

The hesitation was still there at 3800 rpm. Racking my brains I looked further afield and came up with a possible faulty battery. So I upgraded to a new Optima red top 34R. Hesitation was still there so I moved onto the possibility of a grounding issue.

So today I web and got myself some 4 gauge wire an proceeded to add extra grounds from a distributed plate off the negative terminal in the battery to - both grounds on the driver side fender. One ground on the passenger side fender. One onto the alternator. And a ground onto the engine block ground wire.

Taking it for a spin I noticed its much worse: not only does it stumble at 3800 rpm but it keeps stumbling up to 5000rpm. (I didn't push it higher than that.)

Coming back I checked all grounds and resanded the ground on the passenger side where my BHR ground goes to. Still awful hesitation and possible backfiring.

Please any help would be appreciated before I have to take it to a shop and spend my life savings getting to the bottom of this!

Re: Stutter at 3800rpm even after new coils and grounds
 

Hey bro did u get misfires before u changed ur coils? Maybe your cat is clogged. That won't always set off a cel but it can cause hesitation, sluggishness, hiccups.. But it's always a good idea to check ur cat. As it is 1000 dollar peice of equipment you don't want going bad. Are u out of warranty? If not it could be a turbo related thing which I'm not too familiar with maybe someone with a turbo kit can chime in and help you if that is indeed the case.

Re: Stutter at 3800rpm even after new coils and grounds
 

I am having almost the same issue.
2004 rx8
no CEL
no errors produced in ECM
Car starts fine, seems to idle fine.
When driving when reaching around 3500 RPM the car start acting up, hesitation, and really struggles to get any higher.

I have already replaced the Cat. converter, coils and plugs are new, but I almost feel like those may need to be replaced again. Other than that anyone have any ideas what could be causing this?

Thanks in advance,
Dave