michael&audrey

Hi All,

Please don't scream at me to look at other stalling threads. i have read them, and I really can't tell which is really related to our problem.

Anyway, our RX8 car shakes when in idle, but doesn't die, RPMs stay steady, don't flux. If I slide the AT over from Auto to Manual neutral, it calms.. Also, just a smidge of gas in neutral smooths it out even more. The hard idle only happens about a 1/3 of the time, sometimes the car is smooth as silk. Granted, the car has always shaken a bit when idling since day one.

Also, it has died twice on my wife(yes, never when I drive it) in the last couple weeks.

Backstory....

We bought a AWL drive Juke for my wife to drive this winter and I have my 4x4, and the Rx8 sat 5 or 6 days a week, sometimes a couple weeks a stretch this winter. One day, I went to start it, battery was dead. So, instead of jumping it, I had it towed to our personal import mechanic as I didn't want to mess something up.

They put new battery, spark plugs, wires, etc. in, and it started, but was dying at idle and hesitating....they suggested we send to dealer and test compression, so towed it to dealer, they said it was bad shutter valve not a bad engine. I said, ok...as I was ready to scrap for parts.

Once we replaced the shutter valve, all the hesitation issues beyond what the car has had from day one (4speed AT) have gone away, but we notice slight less power when at high speeds (over 80 mph) than it used to.

Well, fast forward six weeks and 3K miles later, and the hard shaking at idle (RPMs stay steady), and the car has died on my wife a couple times this week. Both times she was decelerating from a slow speed to a stop, think pulling into a driveway. The car starts right back up no problem and continues on no problem.

Though our temps have been pushing unusually high here in WI lately, above 90 which is rare, to say the least.

Anyway, we do the rev up to 3000 thing when parking it, and with one exception (lesson learned) have done the flooding thing. We have changed and checked the oil religiously. I also know my wife has a lead foot commuting to IL, and has often pushed the car to 100mph. (spent the money on the right tires too).

Car is throwing no error codes at all.

My question to you all is, I think I might be chasing two separate problems, the shaking, and the dying in low RPM when decellerating.

1. is my dealer lying about not being engine?
2. could it be motor mounts for the shaking vibration?
3. could it be the throttle bottle or a filter plugged? Frankly, I was worried about residue from gas sitting.

Next,

Our options if a bad motor:

Past warranty, and paid for, and is our 3rd car now, so:

1. Sell outright?
2. Trade for a new Rx8? If so, should we go manual or AT for long-term reliability?
3. Just drive it til it won't start no more?

I get frustrated because when I take it to the dealers, they all tell me there isn't a problem, or they want to drive it for a week to see if it can throw a code.

I really don't want to start chasing repairs on the car, $300 - $400 a month pays for a new toy. :-)

Ricky SE3P

iTrader: (10)

make sure the MAF sensor is clean. if you havent changed the air filter in a while, do that while you are at it. if you still have issues and youve done all the other maintenance like you say you have, then its most likely the engine. getting a engine from mazda would be quite expensive, you are going to spend a pretty penny that would be better spent on a good down payment a very nice new car or a used one from a private seller. if the compression is low, sell the car and get either another 8 that you can find on here for example for a good price, or if you want find another car. its all up to you

ARK

Agree on the MAF cleaning and air filter replacement. Might also want to try new coils if they weren't done with all of the rest of that work. Failing coils can cause power loss at higher rpms, perhaps what you are feeling on the highway.

About the work the dealer did before, did he actually do a compression test? If yes, and the results were passing, it's unlikely it's your engine core causing the problem. If he didn't, that's the next thing I would have checked.

BigMikeATL

The first thing that came to my mind was a clogged cat.

nycgps

iTrader: (1)

u don't need to do the 3K thing. it's totally pointless on the newest PCM flash.

and your engine is shot, AT, 1 oil cooler. It's just a matter of time.

MOST dealership these days are loaded with idiots who can't fix **** without a "code", even with a code, sometimes they still can't fix ****, cuz just because it's throwing code for problem #1 doesn't mean replacing problem part #1 listed in the FSM will solve the problem, then they are stunned and wonder wtf happened ? the bible/FSM can't be wrong! That's also why most of them hate working on older cars like my FC. holy crap if I bring it to them and ask them to "hey, fix the 3800 rpm problem" they be like "what problem? FSM don't have anything like that!" and probably cry afterwards cuz they finally realized how stupid they are.

bootslxa

My car is doing pretty much the same thing. I stopped at a stop light and it just shut off.
I started it up just fine but when the rpm's go up at start up, they go back down to 0 and it shuts off again. The engine in the car supposedly only has about 30k miles on it. It's at a garage right now, the guy says he can't look at it till Tuesday. I'm worried whether or not he's even worked on rotaries before though.

bootslxa

I should also say that it was all of a sudden. No shuddering, no loss of power, no weird sounds. It just shuts off.

Razz1

Open up hood check motor mounts.

bootslxa

Could the motor mounts really cause the engine to shut off? I also am doing a terrible job of listing all the circumstances at once. I didn't have any CEL's either.

BigMikeATL

I had engine shut off problems a few times. It was found to be a vacuum leak on the intake. Another time, it was due to a worn out fuel pump.

With such low mileage on your car, I doubt the fuel pump is to blame.

Are you getting any CELs when it stalls?

shakeyourbrakes

iTrader: (4)

i can say one thing, if the car is shaking bad in gear and when you shift to manual/neutral it calms down, theres a good chance your mounts are shot. I actually had mine die once when i came to a stop at a quick red light from 40 to 0 before i replaced my mounts for some reason.
Besides that, I would definitely look at the cat having issues.

BigMikeATL

If the mounts are shot, the vibration could conceivably cause other hoses and connections to come loose.

HiFlite999

iTrader: (2)

The fact that the hot engine starts right back up again after stalling hints to me that compression is "ok". Engine shake from bad mounts could be disrupting airflow or fuel delivery enough to cause a stall at idle. It's rather easy to swap in new stock replacements, so not much labor involved.

bootslxa

I hope it's something easy like that. I wish I could do it myself right now but I just don't have the time. I know it doesn't take that long but I'm in the process of moving and I work full-time now. I graduated about a year ago from college. What I would give to have that much free-time again.

The worst part is that the garage is right across the street from my work so I can see it right out my window every day.

bootslxa

Replaced the MAF sensor and all problems seem fixed. Now I probably need to replace my mounts as well.

shakeyourbrakes

iTrader: (4)

I put it off for a long time, its really not that difficult at all, probably an hour worth of easy work in a driveway with a jack,jack stands, and the DIY on here. I got so used to the shaking I was shocked how smooth everything felt after i swapped them out.