Johnmatheul

cleaned the engine and air filter@@@

superROB23

So the car has been running well. I changed the spark plugs, wires, and coils. I did notice that the car has a jumpy idle when it’s still. Example: one second it’s at 800 rpms then out of nowhere it goes to 500 rpms almost feeling like it’s about to turn off then jumps to 1000 rpms then going back to 800. Now it’s not a consist thing but it has been happening and I thought if I change the spark plugs, wires, and coils it would help, although, this really improved the car in motion but it’s still jumpy when it’s still. The MAF has been changed a while back, I haven't changed any oxygen sensors, the filter is clean, I'm sure or maybe not but I don't think there a vacuum leak. Could the CAT be the problem?

Another thing is the lights inside and outside flicker when I press the window button (the windows are already down I'm just pressing the button repeatedly). The battery is new and I took it to 3 places to check the alternator and they said it’s good. Could there be a bad ground, could this be connected to the jumpy idle? Opinion please...

gwilliams6

yes it could be a bad ground. Check , clean and tighten all terminals and grounds. Also clean the MAF (even if it was changed ) and ESS and check the O2 sensors. You could also have a clogged cat or vacuum leak. I know this sounds like a lot to look at, but all these could contribute to your idle jumping like that. As you go through your progression here, recheck the idle to see what fix may work.

Signal 2

First suspect would be the Idle Air Control Valve (IAC). IIRC they can fail or get sticky but don't throw a CEL. Check the Factory Service Manual. Sometimes they can get dirty and/or carboned up and can be cleaned. Sometimes you just replace them.
Sounds perfectly normal, especially if the window is already all the way down or all the way up and you're pressing the button. Electric motors draw a lot of current starting...and draw a lot of current trying to move the window against the stops.
Stop doing that. Unnecessarily heats up the motor.

NYG1988

Check the cat, mine did the exact same thing. I replaced coils plugs and wires and the issue remained. Finally pulled my cat and it was plugged. Gutted it temporarily put it back on and runs unbelievably smooth now. Going to get a mid pipe and full exhaust in spring.

superROB23

NYG1988, its interesting that you said that, I've gutted my first car, a 1986 ford thunderbird and second car a 1994 camaro and both ran VERY good after that. If I were to gut the CAT in the rx8 and just leave it gutted out would it be bad for the car?

Signal 2

It will be louder, smell like ***...and bigger stinky *** like that huge fat teacher every school seemed to have, worse than a piston engine. It may throw a CEL and performance gains will be marginal...if at all. You also won't pass emissions if you have them in your State. I'm way not a tree-hugging global warming kool-aid drinker, but IMO, IF you intend to remove the cat's functionality (even though it may not be bad or the source of your idle issue), getting a mid-pipe/test pipe might be a better option until you know whether you'll like the car that way. Cats are expensive.

FWIW, a quick search turned up this:
https://www.rx8club.com/series-i-tec...c-test-172129/

RIWWP

iTrader: (2)

Cat removal is a proven power gain, not large, but one of the few easy gains we have.

It will also remove the direct link between ignition failure causing cascading failures that end up damaging your engine, since there is no longer a cat to clog up to damage the engine.

You will also have rear O2 sensors fail faster, but since it's there for monitoring the cat mostly, it's better to remove the rear O2 (which will cause a CEL) and plug the hole with a $3 O2 plug. Use an AccessPORT or MazdaEdit to block the CELs in the ECU if you don't want to stare at a light.

The other points Signal 2 notes are correct.

NYG1988

I still plan to get a mid pipe, it was just a Friday night and I had rough idle for a while and at buddies place we just pulled it and noticed it was plugged so instead of reinstalling the plugged cat or parking it until mid pipe came in we just decided to gut it. Been about 3 weeks now, car does smell a little but not enough to bother me, no check engine light yet. Also it's not much louder then stock.

superROB23

OK, I checked the ESS and it looked pretty clean. We checked and sprayed the MAF, the air filter is old but not ridiculously dirty. Strange thing is when I put on the AC it started jumpy like crazy, once it started doing that I turned off the AC and it sort of stopped but it was lightly jumpy. Question: besides the MAF sensor on the air box what is the other valve/sensor on the air filter box? Should i check now the oxygen sensors. I cant be the CAT because once the car move there is no lost in power....as far as i can tell.

superROB23

Any guesses guys???

superROB23

OK so now it just shuts off once its warm it starts idling like crazy. The battery light does come momentarily but tries hard to rev to stay on. When I turn it on in a cold boot it turns on fine, no crazy idling.

superROB23

Never mind, the maf sensor I bought on eBay was bad. Replaced it with the one that came with the car. Runs good...for now.

Legot

iTrader: (1)

Congratulations! Welcome to the "zero problems" club, don't get comfortable!

superROB23

Update:

I noticed when i bought the car that the driver side rear was lower then the other side. I replace the shock and spring and its a little better but not even. Could the other side have something different size shock and spring?

04Green

iTrader: (1)

how much gas in the tank, try again with a full tank. the saddle tank can have most of the gas on one side. It is also really hard to find a truly level spot.

superROB23

04Green, so the suspension is not the problem? What could it be than???

04Green

iTrader: (1)

Only thought is that if all the gas is on one side, you have more weight over there. Also, the power seat is heavier than the manual one. Again, more weight on the left side.

The factory springs are really really soft. Adding 50 pounds to one side will make a measurable difference. Also, a flat area to measure from is very hard to find. My garage floor looks level, but if it gets wet, there are 1/4" deep puddles.

how much is the difference? is it still the factory suspension?

superROB23

Ok I got the shock from eBay and it should be the right size of the car. I did buy the spring from a Mazda dealer and well its still low on that side. I have a auto with manual seat.

RIWWP

iTrader: (2)

I highlighted the source of your problem.



Ride height can and will change between brand new shocks of different brands, not to mention between differing age shocks and if one is failing and one isn't.

Shocks should always be replaced in at least identical pairs, if not all 4 at once.

9krpmrx8

iTrader: (46)

The tank keeps the fuel level on both side of the "saddles", there are two level sending units and a "saddle pump" in addition to the main fuel pump.

Suspension sagging is almost always the shocks and not the springs. Doing one side doesn't make much sense, you should have gotten new suspension all around or at least just two new rear shocks. You don't have to go with OEM of course.