Ok, so here's the story:

I have a 1995 Z28 M6, the car has 51000 miles. I bought it from an older guy, and I think that it was rarely driven the last few years before I bought it.
So, the car has been awesome since I bought it about 2 months ago (incredible difference from my '87 2.8L AT...lol)
So I put a magnaflow exhaust (turn downs fo sho) on the car (professionally installed). About a month later I ordered a Moroso CAI, and then installed it myself (keep in mind that I have been working on my own cars for over 8 years, and I have only owned camaros...).
I took it out for a drive after the CAI install, and it ran great! I drove it up to my g-friend's house (about 15 min), then drove home that night. I did a nice freeway downshift on the way home; but it was nothing out of the ordinary: I did not "miss my shift" and the car pulled awesome!
The next morning I drove my car to work (only like 2 mins/one mile+) and it was fine. The only thing that "happened" on the way to work was I caught a yellow, I was cruising in 4th at low RPMs so I put a little gas into it for the yellow, but it ran as usual.
So: I start my car to go to lunch 4 hours later and it is running horrible! The car is knocking like heck, and lacks a lot of power!
I put the stock intake back on, and still no change.
I also checked the MAF, all parts of the intake post MAF for unmetered air, and all the wires/connections I could see related to air; and they are all fine.
So basically, I have eliminated any intake issues.
But the car still knocks/ticks at idle, and the power isn't there. The tick is less when the RPMs are up.
I am thinking that it is a fried plug or wire (or the feakin opti; but it only has 51000!...side note: I changed the oil right after I got it, so I know it isn't an oil prob....).
DOES ANYONE HAVE ANY INPUT OR IDEAS ON WHAT THE PROBLEM COULD BE?
I got new plugs and wires and am going to install them this weekend (hopefully), and we'll see what that brings about..................

 

Many of my son's friends mistake a loose plug leaking as a ticking sound. To me it's a definite "shhh shhhh" sound and not a tick at all. Several people have the problem. Attributable to someone in the past overtightening the plug and stressing the threads. Obviously you could see if that's the case by putting a hand on all the plugs while the engine is cool. Easy enough to check.

The next thing you should check and it's real quick, is while it's running crappy, see if you have any dead cylinders. I like to use an infrared thermometer. You could remove the injector plugs one at a time.

Next thing is any bad leaks in the exhaust.

The next item to check is for a bad lifter. Remove the side closest to the sound and push down on all the rockers at the push rod side. See if any are mushy and move.

 

i had a few similar problems when i bought my 95 lil over 2 yrs ago.. it only had 57,000 on it.. tranny went out around 1300 miles of not driving hard.. then i get that fixed and i'm on cruise going down the highway at about 75 when all of a sudden the car starts vibrating like no other.. that's when i rebuilt my engine cause number 7 rod broke in 3 places.. you could look directly through the oil pan... not saying that you're going to have problems like that, or that you have problems like that, it's just that when you get one of these cars with low miles on it, that means it's spent a whole lot of time just sitting, and that's when a small lack of care can quickly kill off a really nice car..