Is my Trans Am running to rich?

I just had a new high flow exhaust installed on my 92 Trans Am (a 305 TPI). My exhaust guy showed me the soot built up on the (69,000 mi) OEM Cat, it was almost totally plugged. He was concerned that my car was running too rich and ruined the Cat.

I have no lights that say I have a problem and all seem to be working. Tonight I noticed there was soot in the exhaust pipe and put a sheet of paper near the tail pipe and let the car run against the paper. I had my wife gun it a couple of times and things seem to be clean (except for the existing soot on the inside of the pipe).

My question is …
* Is my car running rich?
* Was the OEM cat making the car run rich
* If it’s running rich what could make it do so if all the warning lights aren’t indicating a problem.
* Is there something that can be checked (a test) to show if the car is running rich


Thanks for the advice and comments.


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1992 WS6 Trans Am, 305 TPI, Automatic
Flow-Pro exhaust system.

 

I'd have the O2 sensor scanned and see what it's reporting to the ECM, could be time to replace it anyway, assuming it's the original.

Lots of thing will make these cars run rich, too many to list this late at night

 

i think i'm experiencing the same problem that u r. when i go home for easter i am going to set my timing, and check or replace my O2 sensor and my Coolant Temp sensor.

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86 IROCZ
T-Tops
700R4
305 TPI
3.23 gears
shift kit, manual TC switch, manual fan switch, flowmaster exhaust with edelbrock TES headers& hollow cat, gutted MAF.

 

Check to see if the AIR injection line going to the cat is working properly. If it isn't or if it's been taken off, that will cause your cat to clog up.

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'88 IROC TPI 355, '69 truck 4-bolt, fully balanced, 9.75:1 compression, fully ported '70 truck heads(for now), Harland Sharp 1.6 Roller Rockers, Comp Cams CS 252AH-12, ported '86 TPI converted to speed density, Crane AFPR, Flowmaster 3in. exhaust, Edelbrock TES headers, all emissions equipment is still intact, plan on burning my own chips, many more mods and parts on the way as time and money permits =(
Best E.T. with TBI 305: 16.11 @ 82mph
Haven't been to track with new motor
If you have any questions on converting from TBI to TPI email me at jdkchevy70@yahoo.com
In memory of Dale Earnhardt, I'll miss cheering for that black #3 on raceday!!!

 

Unfortunately, I have found the stock GM eprom to actually run too rich @ WOT. Add a cooler T-stat, relocated MAT and higher fuel pressure and you are compounding the problem further.