750-900

[BigO]

I have developed a rattle at the 750 - 900 RPM level. It is like a harmonic noise, at that low of a RPM it causes a little more vibration then when you are above it. I thought it might be the exhaust clamp. It was not. Has anybody else experienced this and if so what was it?

Thanks

[DmaxMaverick]

A couple possibilities come to mind.

Torque converter bolts. The noise could be the early sign of them coming loose.

Downpipe mounting tab. Some of the early models (including mine) broke and caused the pipe to rattle at lower RPM's. Look at the downpipe through the passenger side fender liner. Lift the liner and use a flashlight to inspect the mounting tabs at the rear of the engine. If one is broken, welding in place will work. Mine has been welded for over 75K and is still holding fine.

Intercooler pipes. They can rub against other things, like the fuel line at the fuel filter, A/C lines, etc. They can be adjusted by loosening the clamp and slightly rotating and retightening them. Make sure they have at least 1/2" clearance from anything. Under pressure, they will move slightly, due to the flexible nature of the hoses.

Also check for anything that may be in contact with the fenders or firewall.