Now that the ignition is working on the white 88 GT, it has developed a new issue. It feels like someone put bananas up the tail pipe when I stomp on the accelerator. It has also developed a really loud but fairly constant pitch whistle.

The whistle was fairly intermittent at first, but now it is pretty constant above 1500 RPM. Yesterday on the way home from work it would only whistle above 2000 RPM and only when giving it throttle. The whistle is pretty constant pitch (really high pitch) which tells me it is coming from something with a constant orifice. Sort of like a coke bottle effect. I can't tell exactly where it is coming from. It seems to be coming from the center of the engine compartment.

My guess is a collapsed exhaust system, but which piece? My two experiences with collapsed Catalytic converters (both V6 Fieros) were not like this. It was pretty obvious and the cars would not go much above 30 MPH. Also, no weird sounds in those cases.

This is the car that had a 3.4l engine swap and may not have a stock exhaust, so SWAGs are solicited.

Any words of wisdom? Suggestions on diagnosis steps?

Thanks

Ray

The honeycomb stuff inside the CAT breaks up in many different ways. Bang on it and listen for rattles.

Yeah either air out, or air in.
Maybe a mouse is jammed in your intake?

I actually considered the mouse theory or maybe a boa constrictor after he ate the mouse :-)

First place to look was the air cleaner to make sure. Ran it with top off for two blocks and still noise. Man, that intake is LOUD.

Will do the knock on the CAT test when I get home.