RX-8 sluggish when hitting the throttle...ideas?
 

Hey guys,

Lately I've noticed that my '05 8 has been pretty sluggish whenever I hit the gas. I'll hit the pedal and for the first few-thousand RPMs, the car vibrates from the back a little bit. It's not an insane vibration but it is definitely noticeable and hasn't happened before. Usually, the 8 has some perk to it when I hit the gas in first gear. Nowadays, the car is somewhat slow to respond to me hitting the throttle. I even tried to put the car in park and give it a few revs. Same thing happened, vibration.

I've had the car for 2 years now and I definitely realized that this is not normal. It has never done it before.

Does anyone have any ideas of what it could be?

Please give us some more info... What service and parts has the car had? How many miles on , spark plugs, coils, wires...Have you been having any other problems. What mods have you got? Have you decarboned the engine?

maybe is the engine mount.

Could be...

...along with 1000 other different things. Until the questions that Old Rotor asked get answered, along with probably 3 or 4 other rounds of questions, it will be hard to nail down.

When I bought the car I had the engine mounts replaced because of the TSB. The engine flooded about a month ago and got it de-flooded by the dealer. I have about 34k miles on it. Dealer said I should wait until 38k to get plugs. I have 0 mods besides wheels. I don't have the records of when the plugs, coils were changed last because I bought it used. The oil is full.

Today I redlined the car and it seemed to go away for about 10 minutes. Then when I parked, I revved it and it vibrated again.

It also feels like the vibration is coming from the back of the car

clogged cat? :dunno:

(the fact that it recently flooded could point to this)

Was the TSB to route the oil recirculation to the engine instead of the intake done?
Have you had your car parked for a while?
What are your tire pressures?
How bad do your plugs look?
When you drive your car hard does your cat glow?

+1 my thoughts exactly

Flooding could have damaged your plugs. But it could be other things as well such a a dirty MAF and oil soaked filter due to oil in the intake from overfilling. Either way you are due for some things.

1. Check the intake tract and clean the MAF sensor (easy)
2. Change the Spark Plugs
3. Change the Spark Plug Wires
4. Change the ignition coils
5. Change the air filter
6. Run a can of BG 44k through a full tank of gas
7. Check to assure your SSV valve is not sticking (search)

If you can, have your cat checked as well, a clogged cat can ruin your motor, coils, everything.

Good list of things to do!! "9krpmrx8"

Generally speaking, sluggish throttle response and vibration while accelerating are caused by bad motor mounts. I know this engine requires special care and feeding, but it's worth putting it up on a lift to check the condition of the mounts anyway.

Vibration makes sense for a motor mount to me...slow throttle response does not. Anyone care to explain the relationship to me?

^^ I would do as he says, it might just need to seafoam it!

Bad motor mounts flex more than good motor mounts. More flex means the mounts absorb more of the engine torque instead of transmitting it to the frame, so the car accelerates more sluggishly.

A couple people I know had to replace their motor mounts in their cars, and they said it felt like they'd upgraded the engine too.

Throttle response = Pedal down to engine rev...not acceleration. And once you start moving the wheels they become the point of least resistance thereby getting more power so while your initial acceleration may be delayed slightly...slugish would not be the word I would use to describe it.