Still missing after plenum fixed
You can change spark plugs, so, you can do a compression test.
Most major parts store will rent you the gauge. If you don't have air, then doing a leak down test is gonna be problematic. 
For the compression test, just remove all the spark plugs, and also the ASD relay. (removing the relay deprives power from the coil, and injectors, so, it is a bit less hazardous to your health.)
Prop the throttle wide open, screw the gauge into #1 cylinder, and crank the engine. You will hear it 'hit' the gauge. Let it hit 5 times, read the gauge, record the number, move on to the next cylinder. After you have done all 8 dry.... Start over again with #1, this time, put a teaspoon full of oil into each cylinder before testing, record those numbers too, and then post 'em up here.
Most major parts store will rent you the gauge. If you don't have air, then doing a leak down test is gonna be problematic. 
For the compression test, just remove all the spark plugs, and also the ASD relay. (removing the relay deprives power from the coil, and injectors, so, it is a bit less hazardous to your health.)
Prop the throttle wide open, screw the gauge into #1 cylinder, and crank the engine. You will hear it 'hit' the gauge. Let it hit 5 times, read the gauge, record the number, move on to the next cylinder. After you have done all 8 dry.... Start over again with #1, this time, put a teaspoon full of oil into each cylinder before testing, record those numbers too, and then post 'em up here.
A similar thing was happening to me recently and it drove me nuts. I did everything including a tune up and the plenum with no results. I did notice during the tune up that the little metal sleeves where the plugs go where just about touching the spark plugs. Removed those little sleeves and now it runs perfectly fine again....not sure if this is the case for you but its easy to check off the list if you just take a look.
You have already replaced the pick-up coil. That's the cam sensor.
Vacuum leak could definitely be a problem...... but, the gasket at the back would be more of an oil leak, than anything else.
Vacuum leak could definitely be a problem...... but, the gasket at the back would be more of an oil leak, than anything else.
Yeah I took it all apart, had to blow off the rest of the day after I took lunch but oh well, and it didnt help any except for the oil leaking, but no difference in driveability. Gonna check out those plug sleeves as mentioned by trustyrusty







