help vtec stopped working

[blight]

b16a in a 2000 si

vtec stopped working im having a hard time figuring out why. it works at first start up but after a few pulls in vtec (like maybe 3) it stops working. some times not at all. oil is full, slight oil leak from head on passenger side, no check engine light starts fine runs fine just no vtec. the plug by the oil filter looks like it was spliced into at one point but its looks fine i have not check it yet. it also use to idle at 3k till i came to a complete stop (when vtec works it does this still) but now it only does that when vtec works it now doesnt idle like that most up to 2k then goes down to about 1100 at stop... i cant figure it out. this is the only problem ive ever had with the car. the car has 104k on it as far as i know it has not been ripped apart it looks all stock. the only things i got was a cai and a aem fuel filter (cam with the car when i bought it back in october)

vtec worked until about 3 weeks ago or so. now i live in anoka mn. its cold as f out here dont know if that has to do with it really.

does anyone have any ideas? i could really use some help. i want to fix it before summer.