whats good fellow 8 lovers i was wondering what the normal idle speed for the eight is my 8 idles at around 850 to 1000 rpm and sometimes drops a little lower and then shoots right back up but just for a real quick sec not like a bad IAC juas a quick drop in rpms please get back just wondering.

 

Good question. It feels like a misfire because the idle dips and the exhaust note is different. I've hooked up a scan tool but there's no misfire faults. Also thought it might be a bad coil but haven't had the chance to test it...

 

mine does that, i have few mods and stuff. Il sit at a light and it will idle about 875 to 980, then all of a sudden it sounds like a misfire and drop to mid 750. Doesnt happen all the time every once and a while. I Have the AP hooked up and shows the RPM level..

 

huh thats strange im asking because its my first rotary engine powered car i love it

 

My '06 is stock, and does not do that. Idle is steady, pretty much in the range yours normally is.

Ken

 

Mine idles smooth too. Please give us the history on your car. The service it's had and parts replaced.

 

it just has a cold air intake on it

 

is your air con on when this happens? could be the air con pump cutting in and out?

 

Mine idles at around 850-1000. Without the dip. Mine is a stock mt though. The only time my idle is not that is when i start it from being cold and it is all the way up to 2000 and goes down slowly.

 

Normal to some extent but I would change the coils and plugs because it's never a bad idea to be safe no matter what cost IMO.

 

mine does this but only when warm or with the AC on. it never drops below ~700 though. 06 AT.

 

Well i checked out the coils and they're all right. My friend thought it might be a very small leak in the intake...like a vacuum hose is cracked. I don't know what else i should look into..

 

yea mine has 36xxx ill change the plugs what should i change plugs wires and?

 

if you have the accessport, you can set the idle speed to whatever you like.

mine is set to 950 rpm. It doesn't dip or get rough. smooth like butter.

 

Welcome to 2004.

 

gettin one this winter

 

I'm hunting down this problem as well... Mine will drop to about 300rpm and the ecu will kick it up over a thousand trying to "find" the correct idle speed. It doesn't die, but it's running pretty bad. This only happens when the rpm drops from high speed, like if I'm approching a stop and drop the clutch. It will idle fine otherwise.

I cleaned the MAF and have new plugs and coils. No misfires, no codes at all.

This seems to happen for several drive cycles after I disconnect the battery.

2004 6-spd. 60k, all stock.

I've searched and found lots of suggestions, but none are working for me, dealer says this is normal...

 

If you set your idle to 4,000 rpm, you can burn out all the time. It's pretty awesome.

 

Please give us the history on your car. The service it's had and parts replaced. Model, type of driving it gets(long commutes, short trip), fuel used(reg or prem), oil type and consumption, ever flooded, red lined, mods installed. Have you ever run any engine de-carbon cleaner to improve compression? Just any thing that you can add.

 

/\ - I bought it at about 40k so what I know has only been in the past 20k.

No major maintenance, oil changes (Castrol GTX 5W20) and it takes about a quart every 2-3 months, a few Mazda recalls, new plugs and coils (as of yesterday), and I use premium only no premix or additives.

I was hoping the coils would solve this, but it died backing down the driveway.

I installed a Racing Beat intake and ram duct about 2,000 miles ago.

Never flooded to my knowledge, mostly a long commuter car, but I wind it up through the gears and hit 9grand a few times a week... which makes me think compression is good (never used a cleaner).

 

Ok, more info on the idle issue, looks like it might be my throttle body. Apparently these things go out pretty often. I'm doing a vacuum test tonight to rule out a vacuum issue and then it's off to test the TB.

These TBs apparently can develop a delay in response to the ECU when the engine is rapidly decelerating, causing a bad idle idle after decel. Sounds exactly like many of the idle stories I hear on this site that never seem to find resolution...

The part is serious money and the dealer is telling me it's not covered in the extended engine power train warranty. TB not part of the engine???

 

When I had my ECU flashed to the most recent update, I developed a stall problem where I stalled every time I let off the gas. It just wouldn't idle at all, turned right around and went back to the dealer. After a little poking around they sprayed throttle body cleaner into the front end of the air tube after the mass air sensor. Apparently a little carboned up and it took care of the problem. You might want to try giving it a few shots of the cleaner.

 

if your ecu has been reflashed, it is reset and needs to learn the fuel trims again. A common result of this is that the car stalls for a few drive cycles.

if you have the accessport, you can get a map that has the proper starting trims for your vehicle, and thus bypass the trim learning period.

 

I'm hearing lots of things from the dealer... They called today and said the throttle body is fine, I need a new Cat. I don't mind having an excuse for a new high performance cat and muffler but I'm not sure that's going to solve my idle problem.

 

Mine's an 08... About 7k miles on it.

I noticed this dip as well... It's nothing major, just a stutter, can feel it in the shifter when it happens as well as the seat...

If at a dead stop, it will do it about once every 6 seconds (guesstimate).