well... here it goes. I'll try to make this as short as possible... I went and got Gas Monday, on the ride home from work, as it was getting kind of low. I throw $20.00 of the 89 octane in it and ran great all the way home (30 miles). Did some driving later that evening and it drove great.

fast forward to Tuesday morning...
I go to leave for work and get about 1/2 way down my street when the car starts bucking and stumbling a little. I ran it about another 1/2 mile before I pulled over to check it out, as it started to get worse (I assumed that it was just a little cold and would work itself out). I'm assuming that I bought bad gas on Monday.

Anyhow, call the boss... tell him I cant make it in. Change the fuel filter and all is good for about 10 mins. until the new filter gets clogged . I throw more gas in it to dilute the bad stuff that was in there along with fuel system cleaner and the stubling goes away.... great .

Wednesday....
I go to work and ran a "little" choppy on the way in... but nothing serious. It was probably still a little clogged.... but nowhere near where it was. So anyway, I go on my lunch break and vaccume the car out, get my ears lowered, ect... and then before returning back to work, I went and topped the gas tank off with 91 octane and added a little more fuel system cleaner to help get rid of the junk in the tank.

As I pull out of the gas station, I give it a little throttle when I hear what sounded like a very loud knock/ping/tick sound :wtf:. At that point I pulled over into another parking lot and check it out. I was experiancing power loss and it was pretty loud.

When I looked at it, I noticed that the noise is only coming from the drivers side head and almost sounds like air escaping . Either thru the side of the head, thru the exhaust manifold gasket or thru the spark plug hole/chamber. It also sounds like somthing is hitting the valve cover internally (a distinct ticking)... but not sure if it just "sounds" like it (like an exhaust leak)... or if something really is

Anyhow, I had it towed home and looked at it when it stopped raining. With the engine on... I noticed that around the 2nd plug from the rear on the drivers side... if you place your hand on the vlave cover/spark plug cover you can actually feel it "popping" worse than anywhere else on the cover and that's where I left it. I'll get around to looking at it more throughly either later today or tomorrow afternoon.

Sorry for the mini-novel but I want to paint an accurate picture as to whats going on.... so has anyone ever experianced anything like this before? This is so strange... From what I assume, it almost seems like the one sparkplug either a.) come loose some how and is allowing air to get by it or b.) the thread for the plug came loose from the head c.) a valve got messed up

any ideas? What to look for? this car is my only transportation so I 'need' to fix it this weekend sometime. BTW, this is for a Mark VIII DOHC 4.6l

thanks for looking,
-Steve

That very well could have happened.Ive heard of more then one person having a spark plug work its way loose.Check it.

When's the last time the spark plugs were changed and who changed them? I put my money on a loose or stripped spark plug. :(

I suppose it could have been brought about by moderate pinging due to the lower octane gas, or it could of been merely coincidental.

Let us know what you find.