Re: Odd symptom
If the cat is OEM (never been replaced), you'll generally notice a rotten egg smell (sometimes) or a power loss at all speeds, as well as increased gas mileage.
Make sure the transmission fluid level is fine first before taking it anywhere. Once fluid gets low, the transmission will be slow to engage a gear, or if the trans is VERY low, it won't engage a gear at all, it'll sit there and rev.
Oh, if you're careful you can take a rubber mallet to the cat converter as well and tap it gently. If you hear anything shaking or rattling around, it's shot.
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!