That's what it sounds like at least, this knocking noise in the morning i know the engine is tired 2.8 carb's 138k miles. Ok so i had low oil pressure so i changed the electric oil to mechinical guage was going to change the Engine coolant sensor over to mechanical also so disconnected the wire then realized i didn't have the right socket so replaced the wire now i have a high idle at around 1100 1200 rpms and this horrific knocking noise. know i look under the hood around the carb to see if i might have knocked something loose no vaccume hose disconnected oh wait what is this little wire here it is is coming from the driverside about mid engine has a litttle gray connector and is gray with a black strip anyone have a clue all i know is it is hot when the ignition is on but can't find anywhere for it to go

 

I know about where it goes and what it is but I cant think of it right off. If Im not mistaken it does control the idle somehow. Have to check up on it a little. Either that or its a knock sensor connector.

 

Check a little further up the wire as it may be discolored... Does it have a connector on the end or is it a broken wire?

No knock sensor on the 2.8, dude... Not in the F-body at least. 3.1 got it in 90...

 

Wasn't for sure if they had one or not. I know I haven't seen one mine, but then again I never really looked for it either.

 

If it were there, it would be down by the starter in place of the coolant jacket plug .