900rpm shakes

[ponypowa2]

My car has a nasty shake at 900rpm but smooths out over 1000 rpm



Things I replaced recently:

A few vacuum lines

EGR Valve

EGR Tube (it was cracked)

Spark Plugs replaced about 4 months ago (I checked them again recently, no bad plugs)

Cap + Rotor replaced.

Oxygen sensors replaced 6 mo ago.

Replaced/Cleaned MAF sensor

Recent oil filter/ oil change

====

Things I have checked:

vacuum lines

TPS tests out good (according to haynes)

cleaned IAC

Air filter cleaned

fuel filter replaced

=====

could it be a dirty or clogged injector? Is there anyway to test if the IAC valve is working properly?


any help is appreciated

 

[earleys94gt]

My car had a similar 'shake' around 1100 RPM, and it turned out my Harmonic Balancer was going out.

Take a look at the balancer and make sure the rubber seal isn't bad between the two metal pieces.

If you do need one, check out Ford Racing, Pioneer, TCI etc..

 

[tstang21]

My car had a similar 'shake' around 1100 RPM, and it turned out my Harmonic Balancer was going out.

Take a look at the balancer and make sure the rubber seal isn't bad between the two metal pieces.

If you do need one, check out Ford Racing, Pioneer, TCI etc..

+1

look under your hood while your car is running. check to see if the HB is wobbling. its a tiny bit, youll be ok at the moment. just keep in mind. im changing out mine soon. just makes sure the rubber is not coming out. also to note that 1 of my friends on his gt, his is shaking also but its been ok for the last year.

 

[Zero_chance]

+2 . Happened to mine. I have some pics of how bad it actually was. Ill have to find and post them.

 

[Zero_chance]

Well the pic doesnt seem to work but heres a direct link to the pic on image shack. http://img373.imageshack.us/my.php?image=dsc00023ml4.jpg

 

[ponypowa2]

yep you were right it is my balancer (i replaced it 4 years ago).. its spinning abnormally and the rubber is not uniform around :/

no more autozone balancers for me