Loss of Power is Driving Me Insane

:
Mazda RX-8
I have a 07 RX-8 AT with 92k miles. I bought it used from a local dealer and when I bought it, it ran fine for the first month or so. Just recently I noticed the loss of power. I could put my foot to the floor and it would stay in 3rd gear and never go over 4k rpm, but when I let off the pedal it would shift through the gears. I had it diagnosed at my nearest Mazda Dealer and they said that the VDI Solenoid Valve was going and to replace that. I replaced that with no improvements to the performance. I called them back and they said it was the airbox that needed replacing. By this time whenever it would get close to 4.5k rpm the tach would jump up and down from 3k to 4.5k. I eventually replaced the airbox with an AEM CAI. It had a little bit of improvement but still no power. Now whenever I get to 4.5k rpm it sounds like a valve is suddenly opening up and it sounds really loud. I also cleaned the throttle body and that didn't help. Anyone got any ideas?? My biggest fear is that the dealer is sending me on a wild goose chase hoping that I run it out of warranty so they can slap me with a huge bill.
 
Mazda extended the warranty for the motors on the early (pre 08) RX8s and honestly it sounds like yours needs to be replaced. The warranty may have only been to 80k miles though
 
Man U better fight for that free engine. Us 04's are so envious of free motors and free cats haha. Do ur research. If out of warranty don't sweat bro are motors are cheaper then most cars to replace and most of the time u can get away with a rebuild depending on what's going on. It's best u take it to another dealer where they can honor ur warranty if not somewhere where they will fix the problem instead of giving u the run around. Good luck.
 
You should insist they preform a compression test. That is the only way you will know for sure ig the engine is failing. The symptoms you are describing point to a bad engine, but some combination of other things could also explain all of these problems. Something like failed cat causes coils to fail with a side order of bad plugs and a loose ground. Unlikely!

The bad engine, loss of compressionis more likely. it is strangefor it to run as poorly as you describe for any extended amount of time without failing completely though.

Can you give us any more details?
 
I completely agree with having a compression test performed. Have a Mazda dealership perform it. Though, 07s had an incredibly low number of engine failures when compared to 04/05 models.

Is there a MIL?
If so, what are the DTCs?

I also believe you may have misunderstood the dealership- Probably the SSV stuck closed. It's not in the intake housing itself, but the intake manifold and requires replacement of the lower intake manifold.

Outside of that, there is a high probability of converter failure and/or ignition coil failure.

When my engine started failing, I knew it was only a matter of time- Oil smoke on cold starts, flashing MIL at 7k+ PRMS, intermittent misfire DTCs.

OP, if they're are DTCs, can you get freeze frame data?
 
Last edited:
Man U better fight for that free engine. Us 04's are so envious of free motors and free cats haha. Do ur research. If out of warranty don't sweat bro are motors are cheaper then most cars to replace and most of the time u can get away with a rebuild depending on what's going on. It's best u take it to another dealer where they can honor ur warranty if not somewhere where they will fix the problem instead of giving u the run around. Good luck.
A decent, low mileage engine is around $2500. An average used engine with upwards of 100k is $2000. A remanufactured unit from Mazmart with the Remedy cooling system is $3600. I stumbled across my 07 engine and got it for $1600 with 51k. I opted for the 2007 due to the lower number of failures, but realistically, the difference between them is the emissions system (reworked), PCV system (reworked), and engine management. Other than that, they're identical, but it gave me some peace of mind. And rebuilding can be done, but if you've been driving it, the rotor and rotor housing are going to be damaged and would likely require replacement and a decent used set will run you upwards of $600 to $800. Rotary Resurrection, about 40 minutes east of me, does rebuilds at a starting price of $1650, but that is ONLY a starting price and will likely go up due to damaged rotors and housings. Plus there is the expense of removing and replacing the engine assuming you can't do it yourself.
 
Last edited:
When I worked at Mazda we replaced 13Bs in RX8s like they were going out of style, literally had one in the shop every single day. I'm surprised the dealer you took it to didn't want to jump on the warranty engine work, their techs must be spoiled on customer pay work or really lazy.
 
A decent, low mileage engine is around $2500. An average used engine with upwards of 100k is $2000. A remanufactured unit from Mazmart with the Remedy cooling system is $3600. I stumbled across my 07 engine and got it for $1600 with 51k. I opted for the 2007 due to the lower number of failures, but realistically, the difference between them is the emissions system (reworked), PCV system (reworked), and engine management. Other than that, they're identical, but it gave me some peace of mind. And rebuilding can be done, but if you've been driving it, the rotor and rotor housing are going to be damaged and would likely require replacement and a decent used set will run you upwards of $600 to $800. Rotary Resurrection, about 40 minutes east of me, does rebuilds at a starting price of $1650, but that is ONLY a starting price and will likely go up due to damaged rotors and housings. Plus there is the expense of removing and replacing the engine assuming you can't do it yourself.

+1 gotta love the price quotes, saved the op a lot of searching.
 
is it the same kind of issue as we have on 03 speed protege ?

could have the cold weather cause power loss?
 
Back