slight jerking/shaking at idle

[iscrni]

Hi All,

I have been trying to track down the cause of a jerking sensation while in gear (1st or Reverse) at idle rpms. it happens when I go to inch forward or backwards like creeping forward at a stop light or backing into a parking space. It feels almost like a sticky brake caliper (which it's not). I replaced the MAF and air filter and cleaned the throttle body, after it seems to have gotten better but is still present. Also replaced the PCV solenoid just to rule that out as I've read it can cause problems. No CEL lights or pending codes. at idle with the truck in neutral or park the idle bounces a little between 580-630 rpms and can feel a light vibration when it drops and goes back up in that range, A/C on/Off does the same thing. goes away instantly with throttle. It's not the brakes/Rotors because in neutral while inching forward/backwards is smooth, only feel it while the engine is under load. Truck is a 2012 6.2, 140k miles, engine 100% stock.

 

[CleverGirl_]

I kinda have this going on still, but im lazy about it and I keep telling myself its "normal". Have you changed spark plugs cause that is what the townsfolk are going to ask you.

 

[iscrni]

I have not checked/changed the plugs, although it is next on my list to check. my rationale behind thinking it is not plugs or coils is from when I had it hooked up with forscan I did not see anything unusual with the truck misfiring. I suppose it could be a weak secondary plug or something of the sorts. it all started about 2 months ago, originally I was thinking I had a bad batch of gas since it came was smooth one day and after a fill up and a cold start the next morning it started with this issue. although i'm not sure if this is connected, but if i'm in a parking lot and slowly give it gas to around 1200 rpms, sometimes, it will just stay at that rpm with my foot off the gas until I brake or give it more gas.

 

[CleverGirl_]

I have not checked/changed the plugs, although it is next on my list to check. my rationale behind thinking it is not plugs or coils is from when I had it hooked up with forscan I did not see anything unusual with the truck misfiring. I suppose it could be a weak secondary plug or something of the sorts. it all started about 2 months ago, originally I was thinking I had a bad batch of gas since it came was smooth one day and after a fill up and a cold start the next morning it started with this issue. although i'm not sure if this is connected, but if i'm in a parking lot and slowly give it gas to around 1200 rpms, sometimes, it will just stay at that rpm with my foot off the gas until I brake or give it more gas.

Ive seen this reported on this forum, the thread escapes me but i think it was deemed "normal"

 

[stevenstommyboy1]

I have had 4 Gen 1 Raptors of various years and have had versions of this with all of them. Same 6 speed tranny and 2 of the trucks were 5.4 and 2 were 6.2. Never bothered me as the truck was normal otherwise. Current low mile 2010 has the same issue. I chalk it up to a quirk in the tranny or drive train somewhere.

 

[Nex]

140k miles, definitely past time to change the spark plug and wires. I would start here. Hard to tell if the vibration you feel is normal or not over the internet.

 

[julien194b]

What about the mounts ?

Or it's normal bcs engine is running...

 

[TomDirt]

Ive seen this reported on this forum, the thread escapes me but i think it was deemed "normal"

 

[CleverGirl_]

View attachment 421050

Your day is coming lol. Best not have any idle issues!

 

[TomDirt]

"When in doubt, throttle out"