How can this be. 95 Z28 mostly stock. Got it three months ago running mint. Went to the gym came home parked the car. The next morning start it up running like #$%*t. The car seems to shake when idleing low. Runs rougth, it evens sound different. When running though the gears the car shakes at low RPMs. Loss of power. Cleaned the carb, got new gas and even changed the fuel filter. No luck. I see no smoke out the back. No check engine light. Temp is fine. Checked all the wires on the plugs and on the optispark. Could it be a bad wire or plug?

Duke

 

Could be bad 02 sensors, the OBDI is less sensitive. It could also be a bad plug/wire.

 

Could also be a plugged cat.

 

I think you found the problem. You have a carburetor with injectors.

But seriously, I think you confused the throttle body.

My money is on the fuel pump. One second fine, the next second
Went to lunch in my 99 p/up. Went to leave, dead as door nails. Did 2 quick things to diagnose my problem since I didn't have tools. First I released the pressure in fuel rail. Then cycled power on and off 5 or 6 times. Then checked pressure in the fuel rail by pushing the schrader valve and my problem was more dramatic then yours. I saw nothing come out.

The next thing I did was have someone crank it over and banged real hard on the bottom of the tank near the location of the fuel pump. That jolted the motor in the fuel pump so it started and ran fine until I could get to the dealer for another pump and put it in that day.

Your problem is more suttle than that so if the fuel pump is the problem, you will see it by monitoring the fuel pressure. Use one of these.
http://www.sears.com/sr/javasr/produ...id=00902169000

BTW if you have let the fuel level get really low, here's your sign. The fuel pump is the problem.