Weird Idle

[Jettech1]

I think this topic has been mentioned before but from day 1 with my beloved 22 Custom model gasser, it has a weird idle.  It will bump a bit.  It's not smooth at all and never has been.  Not that it's been a problem ever.  It's just weird that this amazing engine has this weird bumpy idle.  I don't get it.  It has never stalled, it just has this, I don't know how to explain it....Not smooth idle is the best I can describe it...lol...After over 37k miles...it's still the same from new and has never changed.  Odd...

[Another JR]

That’s odd. For about the first 30 to 60 seconds after a cold start, my 2021 has a minor bump every few seconds that make me wonder if they are misfires, but it pretty quickly settles down to a very smooth idle. By the time the water temperature is coming up, it’s completely smooth. Have you checked for misfire codes or put a monitor on it to see if it detects misfires?  

[Chuck FB]

Like Jon explained with his, I will sometimes notice what seems like the odd misfire when its started cold although by cold I mean above the freezing point ( I haven't used it enough yet in actual cold Canadian weather to know its reactions ). Initially when it starts its revs up quite a bit but its after it settles down that I have noticed it but only sometimes if I am standing by the front of the truck. When its warmed up or shut off for a while at stops in town I haven't noticed anything. 

 

So your issue, can you tell its doing this as your sitting in the truck and not only hear it but feel the truck have a reverberation travel through objects in the cab. Also what does it do when its warmed up and your in drive with your foot on the brake as that causes a small load on the engine. If you have not taken it to a dealer and not sure if it would have diagnostic warranty coverage now but to have it checked to see if its showing misfires or of course if you have your own fancy diagnostic tools ( I am guessing you don't own ) or have an independent shop you know well to do the check. Also and this may sound odd but when its doing this go to your tailpipe and not only listen but hold the palm of your hand in the exhausts air flow and feel for the disrupted puff feel, if you've been around crappy running carbed engines you will know what I mean !. 

[Jettech1]

On 11/29/2025 at 6:09 PM, Chuck FB said:

Like Jon explained with his, I will sometimes notice what seems like the odd misfire when its started cold although by cold I mean above the freezing point ( I haven't used it enough yet in actual cold Canadian weather to know its reactions ). Initially when it starts its revs up quite a bit but its after it settles down that I have noticed it but only sometimes if I am standing by the front of the truck. When its warmed up or shut off for a while at stops in town I haven't noticed anything. 

 

So your issue, can you tell its doing this as your sitting in the truck and not only hear it but feel the truck have a reverberation travel through objects in the cab. Also what does it do when its warmed up and your in drive with your foot on the brake as that causes a small load on the engine. If you have not taken it to a dealer and not sure if it would have diagnostic warranty coverage now but to have it checked to see if its showing misfires or of course if you have your own fancy diagnostic tools ( I am guessing you don't own ) or have an independent shop you know well to do the check. Also and this may sound odd but when its doing this go to your tailpipe and not only listen but hold the palm of your hand in the exhausts air flow and feel for the disrupted puff feel, if you've been around crappy running carbed engines you will know what I mean !. 

It's weird.  Been there since day one.  Just a little bump here and there, cold/hot, doesn't matter.  Outside temps. don't matter either.  I guess it's just what it is.  Never been a problem and I can't see it ever being a problem.  I was just wondering if others noticed the same thing is all.

[Chuck FB]

It is odd or at least compared to my one 6.6 vehicle I have been around much as an example. Do try the hand test at the tail pipe though, without burning your hand in the process of course 

[Jettech1]

4 minutes ago, Chuck FB said:

It is odd or at least compared to my one 6.6 vehicle I have been around much as an example. Do try the hand test at the tail pipe though, without burning your hand in the process of course 

I have no codes so that eliminates the mis fire.  It's just weird.  But it's ok.  The smoothest idling and running car I've ever had was a 95 E320 Mercedes.  That straight 6 was the most amazing engine along with being powerful and efficient.  I was stupid and bought a 2000 E320 with the V-6.  Nothing but problems with that damn thing.  That's the last Benz I ever bought.

Edited December 2, 2025 by Jettech1

[Pryme]

11 minutes ago, Jettech1 said:

I have no codes so that eliminates the mis fire.  It's just weird.  But it's ok.  The smoothest idling and running car I've ever had was a 95 E320 Mercedes.  That straight 6 was the most amazing engine along with being powerful and efficient.  I was stupid and bought a 2000 E320 with the V-6.  Nothing but problems with that damn thing.  That's the last Benz I ever bought.

I’ve felt what you’re talking about. It’s just the way the engine is. I don’t think about it. 
 

now if you want to feel, or not feel, a silky smooth v8, drive a first gen LS400 Lexus. Eerily smooth and silent. Those cars were next level when they came out. 

Edited December 2, 2025 by Pryme

[Jettech1]

1 minute ago, Pryme said:

I’ve felt what you’re talking about. It’s just the way the engine is. I don’t think about it. 
 

now if you want to feel, or not feel, a silky smooth v8, drive a first gen LS400 Lexus. Eerily smooth and silent. Those cars were next level when they came out. 

YES!!  I was going to buy one when they first came out.  They were phenomenal.  I ended up buying an Acura Legend Coupe in 92 for my wife.  That car was amazing as well but looking back I wish I had bought the LS400.

[Jettech1]

Those were amazing cars.  A 92 Legend Coupe and a 95 E320.  The good old days...lol

[customboss]

On 11/24/2025 at 5:34 PM, Jettech1 said:

I think this topic has been mentioned before but from day 1 with my beloved 22 Custom model gasser, it has a weird idle.  It will bump a bit.  It's not smooth at all and never has been.  Not that it's been a problem ever.  It's just weird that this amazing engine has this weird bumpy idle.  I don't get it.  It has never stalled, it just has this, I don't know how to explain it....Not smooth idle is the best I can describe it...lol...After over 37k miles...it's still the same from new and has never changed.  Odd...

Engine mounts ? 

[Another JR]

1 hour ago, customboss said:

Engine mounts ? 

I’m thinking leaky injector. You get a bump when it drips. It’s not a misfire, but it often feels like one.  Just guessing, though. 

[bruceb58]

20 hours ago, Pryme said:

now if you want to feel, or not feel, a silky smooth v8, drive a first gen LS400 Lexus. Eerily smooth and silent. Those cars were next level when they came out. 

They are great cars as long as you never have to change a starter in them. Don't ask me how I know.