Engine Vibration Issue...help please!

[Justin88na]

Hey guys,

So I am running into an engine vibration issue and need your thoughts on to what it may be. I have been racking my brains and searching but havent found anything that is exactly the same as my issue.

I really have two issues:-Rough idle-At speed roughness

I have already cleaned my MAF and have recently run injector cleaner, engine flush, new oil, and K&N cone filter. This reduced the idle roughness, I would say it reduced ~50%. However at lights I still idle like I have aggressive cams, very lumpy.

Once moving, it happens again but only in a small RPM range. At speeds around 40-50, when cruising, I will give it light throttle, between 1/8-1/4 throttle, around 1800-2000rpms it will vibrate again. Now this is a more of light shaking than a actual vibration. Once I get it above 2000rpms it goes away and is fine.

I still have yet to clean the Idle Air Control Valve, but before I did, I wanted to get opinions on what the issue may be, so I can tackle it with some direction.

I read somewhere that our crank pullies are adjustable with weights to perfect the balance, maybe i lost a weight? There is some lateral movement with my fan clutch(the blades/fan assembly) could it possibly be this? I really am at a loss.... Please, someone give me some direction.
Modified by Justin88na at 7:28 PM 11/14/2009

[mxr662]

check your injectors hot and cold.

http://q45.org/ohminjectors.html

[goody90q45]

...Once moving, it happens again but only in a small RPM range. At speeds around 40-50, when cruising, I will give it light throttle, between 1/8-1/4 throttle, around 1800-2000rpms it will vibrate again. Now this is a more of light shaking than a actual vibration. Once I get it above 2000rpms it goes away and is fine.....

Sounds exactly like a worn transmission mount and exhaust hangers, about $175 in parts from IOS and an easy DIY. Search "transmission mount" to get all the replacement info you'll need.

Follow Andy's advice and ohm your injectors to start solving your rough idle issues. Another simple DIY with a voltmeter.