Rumble at idle.

[DuRsT]

My 1990 fox shook like a mofo at a stop with a stage 3 Trick Flow cam in it.

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[Dfeeds]

Engine cover is attached to the engine so a vibrating engine means a vibrating cover. If it's bouncing around on its own then give it a good tap.

I'm more curious about your oil. Did you check the oil levels? Low oil and/or oil that's not in a healthy state (full of sludge from frequent short trips, for example) will definitely cause excessive vibrations from the engine. It will still run fine, it just won't run smooth. This won't throw a code, either. Your oil life meter is just an educated guess, and doesn't actually know how your oil is doing, but if it's at 19% I'd say it's time for a change.

 

[Coolmanfoo]

Engine cover is attached to the engine so a vibrating engine means a vibrating cover. If it's bouncing around on its own then give it a good tap.

I'm more curious about your oil. Did you check the oil levels? Low oil and/or oil that's not in a healthy state (full of sludge from frequent short trips, for example) will definitely cause excessive vibrations from the engine. It will still run fine, it just won't run smooth. This won't throw a code, either. Your oil life meter is just an educated guess, and doesn't actually know how your oil is doing, but if it's at 19% I'd say it's time for a change.

Thank you so much for this reply. I live in San Francisco so frequent short trips are the name of the game. I'm going to get the oil changed asap. I'm hopeful that will quell some of the rumble.

 

[smbsocal]

It will shake a little but the amount it shakes varies, not sure exactly why. It is the same with most larger more capable engines. Even with it shaking you shouldn't see the RPM gauge bouncing if at all.

 

[FUN2RIDEFAST]

Is it a stumble, like skipping or momentary loss of fuel injection?

It's your ECU making an adjustment. It just doesn't every so often.

 

[RugbyRef]

It's all those pony's in the motor gettin' restless!

Seriously though, this happened in my '18 (or that's what I perceived to be happening) until I too gave it its first oil change.

 

[The_Phantom]

My '18 rumbled some and my '19 does the same. Noticeable if you're looking for it, but most people won't be able to tell. Filled up with Shell 93 Nitro after burning out the dealer junk gas, so we will see if it gets any better.

Now my '02 WS6 with a BTR Stage 4 cam......that's another story.

 

[Coolmanfoo]

So I got the oil changed today and a full tank of shell 91 gas. Car does seem to be noticably more smooth. Even ironed out what I thought may be a "driveline vibration".

Car feels good as new. Thanks all for the info

 

[frank s]

I'm thinking of those S197 Mustangers who had special "hot rod" cams installed; their only purpose was to introduce that rumble and shake so they could pretend they had a classic muscle car of the '60s.

My '18 GT has stumbled once in fourteen months: cold morning shortly after a start from cold, lasted maybe three seconds. In the olden days the wannabees would pull out the hand choke to get that effect.

 

[Grimmer]

So I got the oil changed today and a full tank of shell 91 gas. Car does seem to be noticably more smooth. Even ironed out what I thought may be a "driveline vibration".

Car feels good as new. Thanks all for the info

Sounds like you got it sorted out... I was going to ask if your '16 GT is manual or automatic?

Mine is manual, and my engine holds a slightly higher idle when I first come to a stop. After a few seconds, it idles down to a slightly lower speed. If the car is in gear and I let go of the brake, it idles back up that same tiny bit, presumably anticipating imminent go time. When I hold the brake again after a few seconds it idles back down. However, if I slip it out of gear (technically it is the clutch switch, not the neutral switch) before I let go of the brake, it does not react and stays on the lower idle.

The rpm change is subtle (about a needle width), but changing to the lower idle is just enough to get my car to resonate with that sweet V8 rumble... Subtle enough that I've wondered if it is more of fueling change than an actual idle speed adjustment. I may never have noticed if it didn't make the difference between that resonant rumble and not.

At first I thought you might be experiencing something similar, but reading farther into the thread it sounded more and more different from my experience. Thought I would mention it anyway, in case you are manual and start to notice the idle changing in the future.

 

[JKL1031]

i know wat youre talking about, its normal. I took my car in for a misfire when i was a noob. camaros do it too.

 

[SSG 5.0]

My '18 rumbled some and my '19 does the same. Noticeable if you're looking for it, but most people won't be able to tell. Filled up with Shell 93 Nitro after burning out the dealer junk gas, so we will see if it gets any better.

Now my '02 WS6 with a BTR Stage 4 cam......that's another story.

Which one is faster. Your 02
Old Pontiac or the
19 Mustang?

 

[The_Phantom]

Which one is faster. Your 02
Old Pontiac or the
19 Mustang?

The WS6 is faster.

That said, I purpose built that car so I've got a ton of money in it. Long tubes, cams, gears, built motor, etc.

If I put the same money in the '19, it would be no contest. I also feel the WS6 is more visceral in speed. It's just violent and it's also much lighter than my 'Stang.

BUT...you can't daily drive it. I mean, I've done it but it isn't anywhere near as refined as my '19 obviously.

 

[Andy13186]

try some ceratec with the next oil if its still not smooth enough. Ceratec makes these engines insanely smooth

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