OK, I've done it all. Tried to diagnose this '88 n/a engine noise. I've blocked the ACV, EGR, switched the port sleeves, tried running without the belts on, switched the injectors, checked the exhaust gaskets, moved the port actuators around with the engine running, pinched off vacuum lines. It does it with the clutch in or out. I replaced a bad LIM gasket, but that wasn't the problem either.

The noise is hard to describe. It sounds like a combination of tapping and someone shuffling cards. It's loudest at 1500 revs or so, and I notice it most when I'm driving next to a barrier or curb where the sound bounces back. Theres good power but I'm concerned that something isn't right and might break, plus it's annoying.

Anyone else experience this??

 

Sounds like an exhaust leak. Id put money on it, to the tee with the "shuffling cards" and taping. It may not sound the way I interperated it, but try looking at your exhaust manifold for leaks or the rest of the system as well. Good luck and let us know how it turns out.

 

hm. sometimes injectors can make noise. sounds like a tapping/knocking(not the detonation knock, just a normal knock).

 

i am going to have to agree with the exhaust leak theory. the sound you described seems to fit it precisely.

 

Yeah.. I have an exhaust leak somewhere and it sounds kinda like you described.

 

OK thanks. I'll check the exhaust again. If it's the exhaust, would it still make noise after turning off the ignition and while the engine is spinning down? Because thats what it does.

 

I think it would because as long as your engine is turning at a reasonable enough speed, there's going to be enough compression there to push out the exhaust.

 

yes, its gotta be an exhaust leak.
do this dont check the exhaust by taking it apart becuase i tryed that an got ended up not finding out anything because i couldnt find where it was by checking the gaskets because they were all new.

this is what you do, jack the car up on the passenger side,(make sure you put stands on) then turn the car on, then get under the car, an put your hand near the joints of each connecting piece, basically trying to feel for any exhaust pushing through.

now if you dont find any air then we will know its not an exhaust leak, but i am pretty sure it is.