ON my 2003 Nissan Altima 3.5V6 they have two VVA's, one on the left and one on the right. About 40,000 miles ago I had a garage tell me that the RH VVA was sticking and they got it un-stuck somehow. The engine runs horribly rough when this valve sticks. Now my engine is acting the same way where the VVA is sticking and then Un-sticking itself somehow and then it runs ok again. How can I tell which VVA is sticking? RH or LH?

I found that my VVA's are prone to sticking after 100K or more miles on the engine. This will be decreased if you don't change oil regularly. The varnish that builds up on the valve will cause it to stick and the engine will then stumble and act like it will die at an idle. I replaced both of them and now the engine has not stumbled and runs great. The valve and housing can be purchased but it's cheaper to just replace the actual spool that's inside the housing. It's easy to get at the left head valve because it's right in front but the back one is much more difficult. The right hand head is up against the fire will and the only way to access it is to remove the intake manifold. Just unbolt the manifold and pull off to side and wire up. You won't have to do any more than that to get at the VVA right hand valve.