I have a 91 Camaro RS with the 3.1L engine. The speed sensor went and the I replaced it. Since then when you take off from a stop it feels like the car doesn't have much power and the Tach goes to 6000 real fast. It shifts fine and everything and there are no noises either. Once you get the car going it seems to be fine. I checked the timing and it was retarded to about 4. I reset it to 10 like it should be but the problem remains. I also disconnected the wire from the Speed Sensor and the problem still remains. I need to put new exhaust on it but I don't think that is it. I checked the catalytic converter and there is alot of stuff shaking around in there but I don't know if this is the problem. I also replaced the spark plugs and the rotar button. Can someone tell me what things I need to check so I can get my car back on the road. All of the gauges read normal and the temp is fine as well. Any help would be appreciated.

 

I like your diagnosis, and I think you found the problem! Did you actually take the cat off and shake it? Cool! I wouldv'e just tried tapping it with a screwdriver, which isn't as good of a test. If there's a lot of stuff shaking inside the cat, time to replace it! The pellet beds break up on our old cats after time, and can clog the exhaust. I drove in a friends car to test it, he said it had no power, and damned if he wasn't right- It was hell driving around town; I floored the gas when I got onto an open highway, and all the motor did was go from "hummm" to "HUMMMMMMM", and I wasn't going any faster. I told him my dad had the same kind of thing happen to him, and to check the cat for being clogged. Turned out it was, a muffler shop changed it for him, and the problem disappeared.

A new replacement GM cat will run you a lot of money. Local parts stores usually sell "universal cats" for $100, with a $25 installation kit that adapts the pipes to the car. You can nab a catco (or any other brand you want) high-flow cat from Summit Racing for about $80-$90, and if you get the right one (2.5" inlet, 2.5" flanged ball outlet), it'll bolt right up to the exhaust.