Heavy vibration at idle

[fluffeh]

I've noticed recently that when I'm in gear at idle, my car vibrates a LOT more than seems normal. If I shift into neutral, the revs go up by ~200 and the vibrations go away. Every time I stop at a red light I get this annoying vibration, and it's starting to make me worried something has gone wrong. The only mod I've done to the entire system is a Magnaflow muffler, so I don't know what the problem is.

 

[Whitson Metalworks]

my bet would be a missfire, likely caused by a weak or failing coil, bad wires or plugs. my wifes does the same thing.

 

[Drcoffee]

my bet would be a missfire, likely caused by a weak or failing coil, bad wires or plugs. my wifes does the same thing.

Plugs, wires and don't forget fuel injectors.

 

[T4Rscott]

check motor mounts and trans mount too.

 

[fluffeh]

Wouldn't a misfire trigger a check engine light?

I was thinking the mounts but I wasn't sure because at slightly higher revs it goes away and I thought it would be the other way around if the mounts were worn.

 

[Whitson Metalworks]

Wouldn't a misfire trigger a check engine light?

not always. i accidentally knocked off a plug wire doing my ISR mod the other day and later let the truck run while warming up for 5 minutes or so, no light.

 

[fluffeh]

Hmm. I'll check that out. Gotta find time to get all of my car stuff done. -_-
Thanks guys.

 

[Foo-Fighter69]

You would probably now if you had polyurethane motor mounts in there but they cause vibration at idle.