My '93 went from silent to sounding like someone was shaking a coffee can of marbles everytime I got on the gas. Also would get the check engine light at the same time, on the highway typically.
A simple diagnosis turned out to show that the EGR valve was pretty much blocked/clogged, so they replaced that and the solenoid and all has been back to silent ever since.
I'm assuming they would have already checked that on your car, since you said EVERYTHING has been gone over multiple times, but still just thought I'd post what my issue turned out to be.
A simple diagnosis turned out to show that the EGR valve was pretty much blocked/clogged, so they replaced that and the solenoid and all has been back to silent ever since.
I'm assuming they would have already checked that on your car, since you said EVERYTHING has been gone over multiple times, but still just thought I'd post what my issue turned out to be.