Well, I had a 94' Corvette Coupe, wish I still had it. The light is emission related and most likely is a sensor. I would guess an O2 sensor right off, because when they start to go, the check engine light appears intermittently, and they need to heat up before they start to interact with the PCM. Without any diagnostic test equipment it is hard to say without getting voltage readings on various sensors. When I had my 94' I replaced my throttle position sensor, Map sensor and O2 sensors. I didn't realize how bad the car ran with a bad Map sensor, until I replaced it. When the O2 sensor went, I replaced both at the same time just in case. The MAP sensor should read above 4 Volts between terminals A & B with the ignition on. If not, check terminal C for a 5 Volt reference signal. If you find the 5 Volt reading, the sensor is bad. You should get a voltage drop when vacuum (throttle) is applied. The thottle position sensor (TPS) readings depend on what VIN you have. For VIN 8 and J engines with the ignition on, check the voltage at terminal B, for VIN P and 5 engines, check the voltage at terminal C, the voltage should read less than .5 volts. Open the throttle and the voltage should change and increase smoothly. At wide open throttle position, you should read around 4.6-5Volts. Testing the O2 sensors becomes alittle more involved due to VIN heated and non heated O2 sensors, some having two sensors ahead and behind the cats, either side. even so, I would suggest a replacement every 30,000 miles. Very easy to do. The C5 was a god send with its DIC. Throttle position sensor is available at AUTOZONE and PEPBOYS for $50.00. MAP sensor available at the same stores for around $40.00. O2 sensors available at same stores for around $50.00 each. Not bad considering what the dealer would charge, but the advantage of the dealer is all the diagnostic test equipment, and finding the problem fast. TPS is located on the right side of the throttlebody sitting in the drivers seat. Map sensor located located on top of, and right side of throttlebody from drivers seat. O2's located fore and aft of the Cats in the exhaust pipe. Sorry if you knew this already. To get voltage readings on a sensor that is plugged in, straighten out a paper clip and insert it in the terminal from outside the plug where the wire goes in, behind the plug. Good Luck! An electrical test meter is recommended if you have an LT1. Also the GM Corvette 84'-96' repair manual where I got you the info.
4LT GS Roadster
