De/Accelerator really jerky, sensitive throttle?
 

So I initially had some regret when buying my RX-8 but I'm back months later and having a hoot with it. I had a couple of questions!

My accelerator seems to be jerky on throttle. From coming to a stop or just decel off throttle causes a bit of a lurch when I'm trying to baby the throttle movements too. It's almost on/off switch-like but I do see that very very tiny inputs do make a difference. Is anybody else's throttle like this? I have a Miata so maybe I'm just heavier footed since the throttle doesn't do much on it but the RX-8 feels like it's impossible to have smooth throttle inputs. I tried cleaning MAF, checking/changing air filter, and now considering buying fuel injector cleaner that I can dump in before a full gas refill. I get no CEL. It's low mileage. I don't think it has clogged cats because no CEL and I'm getting like 22 MPG avg on medium trips. Any advice on if I just have a lead foot and bad control?

Have you made any changes to the suspension/bushings of the car?

Mine was similar to what you are describing, but I have practically disassembled and reassembled the car countless times. I also have a rather stiff suspension setup.

If you have mazda edit or versatune you can look into calibrating your maf sensor and injectors which can help smooth out the engine. I found that the stock US fuel map had some strange lean out spots that made the car very jerky in the mid range. I tried a jdm map which avoided these lean spots and is much smoother. The big one to look at would be the linear throttle tuning which has a fairly detailed thread. This simply makes your throttle pedal respond the same no matter what speed or gear you are in. I believe stock 1st gear has it so 30% pedal is actually 100%(84%) throttle%(throttlebodyposition%).....which would be basically an on/off switch.

22mpg is pretty good, I average about 15.5 right now which may be generous since I also run smaller tires than stock (closer to 14mpg?).

Thanks for the reply! No suspension changes though I think the back shocks are busted as they bottom out real easily.

I don't have either turner software but should I assume this is normal? I've just been trying to feather out the jerkiness by really slow decel or clutch work. It happens in at higher speeds too. Going 60 mph in 4th gear, let go of throttle, and lurch. I'm used to seeing this at lower gears on motorcycles where you have to be real crafty with the clutch but never on cars.

To be fair, I did just replace spark plugs + coils and the 22 MPG is theoretical since I'm using a scan gauge. My brakes are also REALLY sensitive but that's a different issue to try and rectify haha.

What rpm are you maintaining when it gets jerky? You don't want to below 3k in most cases. What you're describing sounds normal, but obviously a matter of degrees.

I haven't consciously checked but probably around 3-5k range off decel causes that lurch. It's normally followed by a boomy decel sound out my exhaust (although I do have a TurboXS). If I'm cruising I'll try to stay at 4k just because of the drone at 3k. I know people say to keep the RPMs high but I'm not trying to be THAT guy on the road blasting a concert of explosions going 65 mph.

3-5k is normal driving range so that checks out. Higher in higher gears so you don't lug it. It's a high strung engine so it does take some finesse with the gas pedal. S2000s are similarly jerky. But you can definitely tame it.