Rough Idle

[Ikabob]

Went back to Shell 89 since its on the Top Tier list.

Now trying out 93 Shell. For some reason I'm liking it. Possibly placebo effect. Who knows?

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[NorthernEX-T]

I've noticed the same thing with my EX-T. Sometimes it sits around 700-750rpm when stopped/idle and sometimes it sits around 600. Very weird indeed.

I totally agree. My ex-t does the exact same. @Ikabob next time I drag race I'll try some ultra 94 and L gear and if I'm not running a 15.0-15.2 I'll be more confident in saying 87 is best.

 

[djasonw]

Putting higher octane fuel is throwing your money away. It has zero benefit. The car is designed to run on 87. An interview with one of the car's designers was asked if higher octane would benefit the car. He said no.

 

[NorthernEX-T]

@djasonw Most people understand that on here, but I've tried 91 one time and it did feel smoother. I'm saying I want to defeat the myth that higher octane is better. I am agreeing with you. I will compare my best time of 15.46@89 in S on 87 octane to the highest octane available at the pump (94 in Canada) so we can put the "performance" benitfit to rest.

 

[markfu42]

My civic touring tends to be a little rough at idle, whether it be at a stoplight or just sitting idling. Anyone else have this issue? I plan on bring it up to the dealer when I go get my first oil change.

I have a 2019 Civic SI. When idling I have noticed that the tachometer shows the revs bouncing ever so slightly, like within 25 to 50 RPM. Is this normal? Do you think it is similar to your issue?

 

[TranceFC1]

I have a 2019 Civic SI. When idling I have noticed that the tachometer shows the revs bouncing ever so slightly, like within 25 to 50 RPM. Is this normal? Do you think it is similar to your issue?

Mine does the same. Lately I've been having it raise to about 8-900 when I come to a complete stop then slowly settle down

 

[NoHonor937]

Your rpms should not be bouncing. Mine don’t. On my 97 it was caused by a cracked exhaust manifold. But we literally tried to fix all the other possible issues before then. Distributer, sparkplugs, fuel injector cleaner. It all helped to some degree but exhaust manifold being cracked definitely was the culprit. I’ve heard that the manifold is part of the engine but there may be an exhaust issue robbing you of power. If you can look through your exhaust pipes and such and see if anything is loose, cracked, rusted etc. I’m not what mods you’ve done but let’s say you put a downpipe in, could’ve not installed correctly and be letting air escape. Just my thoughts

 

[markfu42]

Your rpms should not be bouncing. Mine don’t. On my 97 it was caused by a cracked exhaust manifold. But we literally tried to fix all the other possible issues before then. Distributer, sparkplugs, fuel injector cleaner. It all helped to some degree but exhaust manifold being cracked definitely was the culprit. I’ve heard that the manifold is part of the engine but there may be an exhaust issue robbing you of power. If you can look through your exhaust pipes and such and see if anything is loose, cracked, rusted etc. I’m not what mods you’ve done but let’s say you put a downpipe in, could’ve not installed correctly and be letting air escape. Just my thoughts

I have only had the car for a month. I can hear or feel no change. Just can see the line move ever so slightly. Please see video below;

 

[NoHonor937]

I have only had the car for a month. I can hear or feel no change. Just can see the line move ever so slightly. Please see video below;

Yet there’s no rough idle? Then why did you comment as though you were having idling issues? I’ll watch mine one day and tell you if it’s normal. I doubt it. Your idles should be consistent and not dropping although yours arnt bouncing in the way you explained. I was expecting bounces from 700-600 and back and forth.

 

[markfu42]

Yet there’s no rough idle? Then why did you comment as though you were having idling issues? I’ll watch mine one day and tell you if it’s normal. I doubt it. Your idles should be consistent and not dropping although yours arnt bouncing in the way you explained. I was expecting bounces from 700-600 and back and forth.

"I have a 2019 Civic SI. When idling I have noticed that the tachometer shows the revs bouncing ever so slightly, like within 25 to 50 RPM. Is this normal? Do you think it is similar to your issue?" Was my initial reply. Just was wondering if it was normal so I wouldn't have to goto the dealership and bother them about it. Thanks!

 

[NoHonor937]

"I have a 2019 Civic SI. When idling I have noticed that the tachometer shows the revs bouncing ever so slightly, like within 25 to 50 RPM. Is this normal? Do you think it is similar to your issue?" Was my initial reply. Just was wondering if it was normal so I wouldn't have to goto the dealership and bother them about it. Thanks!

Fuck it it’s under warranty then let em deal with it. I have never seen my rpms bounce on my car but I’ll watch more carefully. I believe it’s an air or exhaust issue.

 

[saiko21]

"I have a 2019 Civic SI. When idling I have noticed that the tachometer shows the revs bouncing ever so slightly, like within 25 to 50 RPM. Is this normal? Do you think it is similar to your issue?" Was my initial reply. Just was wondering if it was normal so I wouldn't have to goto the dealership and bother them about it. Thanks!

It moves a little on my 2019 Civic Si as well. You need to look at the tacho to see if its moving or not.

 

[NoHonor937]

"I have a 2019 Civic SI. When idling I have noticed that the tachometer shows the revs bouncing ever so slightly, like within 25 to 50 RPM. Is this normal? Do you think it is similar to your issue?" Was my initial reply. Just was wondering if it was normal so I wouldn't have to goto the dealership and bother them about it. Thanks!

So I went back and watched mine and it does slightly move. I see no reason for concern. If it’s making more than millimeters of movement such as the 100s bounce range than yes that is a cause for concern. Your rpms bouncing a 100 rpms is enough to cause stalling potentional. Went through with my 97 civic for a couple months before I grew tired of it and replaced the manifold.

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