So recently when cold starting my exhaust sound seems very choppy for a while. The RPM isn't changing at all and it doesn't do it when at idle. Just when accelerating.
I will try and record this tomorrow in the morning if possible.
I don't feel any loss of power at all. And my compression seems fine since it starts hot or cold first time, every time. Also the other day I was in a rush and accidentally turned the car off when still cold and it started right up no problems.
I do have an exhaust leak where the decat pipe joins the downpipe which I keep meaning to have fixed but never have the time. But that hasn't got any worse and this choppiness is new.

Again i'll try and record this tomorrow morning. I'm not paranoid about car noises usually, but this does seem a bit weird. And the fact it goes away when warm.
I've done basic troubleshooting like reading engine codes etc. Other than the code bitching about me removing the secondary air pump there is nothing.

I also reset the ECU by stamping on the brake 20 times etc... oil thing goes side to side. Let it idle for 10 mins. You know the drill.

 

Okay so I recorded best as I could the choppy exhaust sound. The one time I want to record it and it barely does it. I am definitely feeling a loss of power now. Going up a moderate incline my car usually flies in 3rd gear and now it doesn't go right. The exhaust sound nothing like it used to either.

Could this be a stuck intake valve?

 

I mean I don't mean to make you worried but from what you are saying (I can't listen to the sound because I'm at work) It sounds like you blew and apex seal. It happened to my car it sounded like a truck that ran really bad and then it started blowing lots of smoke out of the exhaust you may or may not of the smoke part depends on what seal blew out I believe but i did have a big loss in power. But my car also started up fine and under 5 seconds hot or cold but the engine was junk.

 

Thanks for the input. I'll look into this some more. I sure hope not but I feel like i'd be experiencing more of an issue if I had a blown seal. My motor isn't running like junk, it still has a fair bit of power. Just noticeably less than a couple weeks ago. The engine runs smooth until it does the choppy thing. And thats usually from like 2500-4000rpm then it goes away.

I'm going to go though a checklist of things tomorrow to see if I can solve the issue:
Cleaning MAF
Checking ignition coil ground.
Checking battery connections
Unplugging baro sensor temporarily to see if its failing (this has caused issues for several people, not usually choppiness though).

If none of those are the issue then i'll start going deeper:
Removing and cleaning secondary intake valve.
Changing fuel filter (I actually have no clue when it was done last)

I suppose it wouldn't hurt for me to go and get that exhaust leak fixed too.

 

Is the check engine light flashing during the choppy condition? Does it happen at the same rpm? Does the car idle fine? Is there oil in the intake?
If you'd thrown an apex seal it would show up first and foremost at idle/start-up. I was going to say it's your cat, but you don't have one, right?

Don't worry about the fuel filter, there is nothing to be done there. It's in the fuel tank.
It could be something really random like your clutch safety switch being poorly adjusted and creating an intermittent signal. There was a thread not long ago about this.
Further on that note, it sounds like your clutch may be starting to slip. When it does the engine load decreases, which could be what you're hearing. Would explain the loss of apparent power too. Do revs increase without a corresponding change in speed?

 

No check engine light flashing. It always happens in the lower range. Between 2500-4000 usually in 2nd and 3rd gear. Its fine at higher RPM. There is no oil in the intake as I actually checked it yesterday to look at the throttle body.
Car idles fine. It starts first time hot or cold. I don't have a CAT as you said. Just had a new tranny and clutch put in less than a month ago so its definitely not slipping.

What you say about the clutch pedal being poorly adjusted though... that makes sense. Because my car often clunks into gear with the clutch fully depressed. The car will jolt forwards a bit too. So the pedal might be poorly adjusted for sure.
Is adjusting the clutch pedal easy or is it something I better pay my mechanic to do?

Thanks

 

Adjusting the pedal is easy, just takes a small wrench (7mm i think?). The thing is, if it's poorly adjusted, the clutch will wear more quickly since it's never fully disengaged, and can glaze. That would make slipping more likely. Suggest you test for slipping just in case. Just mash the gas at low speed in 4th and see if the rpms go up without change in speed.

 

Sweet. Guessing its like a throttle cable where you have two nuts. One adjusts and one locks? Which way do I adjust it to loosen the clutch, towards the firewall or towards the cabin?

Thanks

 

https://www.rx8club.com/series-i-do-...stment-245742/
4 min job crazy easy to do

 

Gotcha, rotate nut clockwise 1 full turn at a time. Thats a good thread but the images don't work.
I'm gonna do this tomorrow and then i'll report back to see if this fixed the issue.

Cheers

 

Its hard to hear from the sound clip, but check to make sure you don't have any loose heat shields on the car, around the gas tank or specifically around the catalytic converter. It almost sounds like a rattling heat shield in between shifts.

 

I'll check the heatshield around the gas tank. I don't have a heatshield around the decat pipe, I used titanium wrap on that. It would make sense since it only does it sometimes and only in a specific RPM range.

 

Keep us posted on what you find out.