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noticing a vibration at 2-3k rpm and at 4k and above that the engine doesn’t seem that smooth
it feels like a light backfire or misfire and happens in all gears
dont Think it’s tire related as it sounds the same regardless of speed/rpm
Are these engines just a bit rough / burbly at certain rpm’s? How smooth should it be
Mine is 4.2L SC (2008) but I get that too.
The engine/trans mounts have most likely hit EOL or near and have leaked out the hydraulic fluid.
If you determine this is the issue, I found 2x engine and 1x trans for under $200, assuming the 5.0 and 4.2 use the same ones.
@Cliffords
I've posted about mine a while back. Starts smooth, but once it is warmed up and drops RPMs I get a shimmy I can feel.
I took it to an Indie and they confirmed while the mounts aren't shot, they are nearing EOL.
Last edited by Circumnavigator; Nov 2, 2025 at 03:39 PM.
Why wouldn't it be smooth? There is no situation I could think of as to why it wouldn't be as silky as it is at any other time. Plus, if it WASN'T, how would I know? What would it cause? If it never happened, what would it matter? As far as finding out, I don't want the pistons to swap holes at 6,000 RPM in Park.
Mine is 4.2L SC (2008) but I get that too.
The engine/trans mounts have most likely hit EOL or near and have leaked out the hydraulic fluid.
If you determine this is the issue, I found 2x engine and 1x trans for under $200, assuming the 5.0 and 4.2 use the same ones.
@Cliffords
I've posted about mine a while back. Starts smooth, but once it is warmed up and drops RPMs I get a shimmy I can feel.
I took it to an Indie and they confirmed while the mounts aren't shot, they are nearing EOL.
was thinking engine or trans mounts as well… not really looking forward to that DIY
Mine purrs as well. A failed injector can cause all kinds of issues. As does a dirty PCV. And we all know about the importance of very timely oil changes.
This would be my first port of call The early cars had the first incarnation of the Bosch injectors and have often been problematic. The replacements appear to be much more reliable.
This would be my first port of call The early cars had the first incarnation of the Bosch injectors and have been often problematic. The replacements appear to be much more reliable.
if the injector was failing would there be additional symptoms?
My car is throwing no codes, cold starts ok, no fuel smell.
it makes about 21mpg highway and 8-11mpg city (nyc)
How smooth is your 5.0 sc?
