Ok today im driving and i turn the defogger on... (ac on front windshield) and in idle the car shakes like crazy... a lot of vibration.. it didnt used to be like this before.. it idles good at 700 rpms... when im approachinga red light i get these vibrations right before im about to stop.. it vibrates a little heavy for like 3 seconds right after i stop... but then goes away... wtf could that be??

by the way full tune up was done and car runs well otherwise...

 

Is your motor struggling as your stopping ? Meaning is it going below idle and then recovering and thats when you feel the vibration ?

You might just need to Clean your TB and IACV so your motor stays up in the revs as you slow down and stop.

Just an idea

 

no no its not that.. its not struggling.. it just vibrates a lot for like 3 seconds when im almost stopped then it calms down... its weird.. but when i turned on teh ac today i felt a **** load of vibrations in the floor...

 

look @ ur rpm when your stopping. what's ur idle in D while @ red light? I get the same thing, but that's because my rpms fall too low (~500rpm) and the engine is struggling to power everything. My friend helped me to clean the IACV itself, but like dumasses we didn't even look @ the opening in the manifold. (which is prolly what's causing my low idle)

 

nope rpms never fall below like 550

 

that's a little low, which is my problem. I tried adjusting the idle by using the plastic screw, but it had no effect. I REALLY need to clean the openning in the engine to which the IACV is attached to.