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Rough Idle

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Old 06-18-2009, 09:29 PM
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Pain Is Weakness
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Red face Rough Idle

Hello,


Two days ago I pulled up to my house, the car was in neutral, and A/C off, I felt the car tremble slightly n BAM car stalled out. Turned it back on and sat in it for about 2min and nothing, idle was fine as if nothing had happened. However (occasionally does not happen always), after driving for about 30-40min if i reach a stop light or something the car might do it, might not. Its frekin weird n driving me nuts. Also when it does do this the car trembles. Now my findings; Last weekend I was cleaning out the engine bay and shineing hoses ect..so i decided to pull the Throttle Body and see what it looked like inside so i did, The TB was dirty as hell, so my hypothesis is that the throttle body heats up so much that the little butterfly plate expands slightly and due to carbon build up around the butterfly plate almost restrics flow 100% causing the car to eat ****.

So yea any input/advise will be greatly appretiated.
Old 06-18-2009, 09:43 PM
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Please give us the history on your car. The service it's had and parts replaced. Model, type of driving it gets(long commutes), fuel used, oil type and consumption, ever flooded, red lined. Just any thing that you can add.
You might have some carbon build up from a lot of short trips and not seeing the red line much. You might run a few cans of Seafoam, BGK44 or another carbon cleaner.
Old 06-18-2009, 09:53 PM
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I bought my 2005 6sp mt w/29000miles on it, rite off the bat I began doing the tsb's myself, I replaced bat-optima red top, starter-oem, and recently did the BHR ibgnition upgrade. I bounce off the rev limiter maybe 5times a day, I use BP 93 octane fuel, premix w/idemitsu, n use castrol 10w30 gtx change oil every 2k top of every 500or as needed.
Old 06-18-2009, 09:54 PM
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4got 2 add I seafoammed last month, also the car has nvr been flooded since I've owned it, it has about 37k on it now.

Last edited by Jonathan11; 06-18-2009 at 10:00 PM.
Old 06-18-2009, 10:14 PM
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damn. that's some regimen.
Old 06-18-2009, 10:22 PM
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You might want to check and clean the butterfly in the throttle body. There is a thread in here that someone have the same problem as you. There is a DIY on how to clean the throttle body as well.
Old 06-18-2009, 11:29 PM
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yeah I also say check your thottle body..could prob use some cleaning
Old 06-18-2009, 11:34 PM
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ya tb..clean it
Old 06-18-2009, 11:49 PM
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You might also want to try resetting your ECU. I had the same problem, and reset my ECU to get through emissions because I also had a CEL on, and it fixed all of my problems. She runs like a pure bred now.
Old 06-19-2009, 07:39 AM
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Ill clean the TB 2marro and report my findings, ill also rested the ECU while I'm @ it, tho I don't have any cells. If the cleaning of the TB doesnot work guess its off 2 the dealer for a compression check "/
Old 06-19-2009, 09:17 AM
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The first time I reset my ECU, I didn't have CEL's either, justs a rough idle and it fixed the prob. Couldn't get it started one morning and the CEL came on, then I reset the ECU and the starting problem went away along with the CEL.
Old 06-20-2009, 11:06 PM
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Okay so today I will be cleaning my throttle body, and doing the TB bypass mod as well. I hope this helps. I will keep you guys posted. Thanks for the input
Old 06-20-2009, 11:13 PM
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Heh, I'm surprise that nobody here mention spark plugs, plug wires, and coils. The culprit is one of those three... I doubt that it's the TB.
Old 06-20-2009, 11:15 PM
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did the BHR ignition upgrade a month ago. And yes i verified everything was installed correctly. It defiantly improved w/the ignition upgrade, but its still faintly noticeable, so im going for the TB.
Old 06-21-2009, 12:27 AM
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its the stock air box struggling for air, therefore u throttle body+ engine does like a quick shiver and sounds slightly higher than normal. Even if you have a K&N drop in as I did it still does. Once I changed my stock air box to a AEM cold air intake, I get no more Shivers' or loud idling. That was like 1 weeek ago.
Old 06-21-2009, 07:05 PM
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Well, today I did my rear diffuser, Throttle body bypass & cleaned it out, and also did the better flowing air box mod. O and i also reset my ECU. Once the car warmed up i noticed a slight difference when shifting in the low RpMs, not much of a difference up high (past 4k) but i must say that there is a definite difference in IDLE. So i recommend cleaning out the TB and if your in a warm climate like Miami I also highly recommend the TB bypass good ****!. My next thing is going to be replacing the motor mounts im almost 100% sure they are going bad.


Thanks to everyone for there input
Old 06-22-2009, 05:57 PM
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2day I put my mod 2 the test, here in Miami we hit a record 97degrees F. The car marked 100F. Anyways, a 30min drive stuck in traffic on the palmetto followed by some sprited driving,mind u this w/the AC @ full blast, all I can say is wow! I recommend this mod 2 anyone experiencing the same problems I was. If u need any help w/any of the above mods feel free 2 PM me. N if ur local here in Miami I wouldn't mind helping out a fellow rx8 owner
Old 06-22-2009, 06:21 PM
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Just letting you know.....

Motor mounts should be covered under warranty. It seems like you have the same year and albeit a bit more miles that me....similar cars.

The newly updated motor mounts have shields around them to protect them from the heat (the reason why the OEM mounts failed). If your mounts are bad, the idle is definitely going to show a lot of vibration into the cabin.
Old 06-22-2009, 06:40 PM
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O.o So you're saying that my DIY intake mod and the TB Cleaner is working out for you? Nice.
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