hi evan, yes there are a few tricks, but things have to be right.
your fuel mixture HAS to be 14.7 to 1. when that is dialed in you can drive the car for 50 to 100 miles with higher rpm then normal. as in droping down one gear on the freeway. this heats up the cat that burns off build up in the cat.
mixture is very important!!!!!
second, which may be faster is to remove the power boster line and let it run lean for about 20 minuites. this shoud have the rpm about 2 thousand.
before you start get some tailpipe readings with the cat at normal temp. and post them here.
don't waist your time if your mixture is not correct.
one more thing, with the booster line off, some short squits with carb spray toward the 02 can help.
imho
rich

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88 300E White, sold 9-04
88 190E Black 2.3 sold
90 300CE White, Grey sold 12-24-04
92 400E White,Grey Sold 5-06
90 300CE 91K Signal Red,Black Sold 2007
1989 300CE Smoke silver,Tan Sold 1-08
1993 300E 3.2 M104 motor
1991 300CE White,Grey
1994 E420 beautiful car,gone to new home
1994 E320 Smoke an Parchment.Beautiful car