Part Throttle & Idle Stumble
Thread Starter
2nd Gear
Joined: Aug 2013
Posts: 2
Likes: 0
From: Lake Orion Michigan
Part Throttle & Idle Stumble
I have been after this problem for the last few years. The car, at times, would stumble and pop in the exhaust when trying to accelerate at a moderate rate. The problem was the Mass Airflow Sensor. I cleaned the sensor and repaired the wire connections to the sensor. I found the yellow wire to be broken internally of the insulation near the connector. To check if the MAF sensor is the problem, disconnect the sensor and allow the engine to set a code and light the Malfunction Indicator. The engine will now run in the Speed Density mode. If the problem goes away, then you need to investigate the MAF sensor. I used CRC Mass Airflow Sensor cleaner and disassembled the sensor to clean it completely. I’m in love with my Corvette again!
Thread Starter
2nd Gear
Joined: Aug 2013
Posts: 2
Likes: 0
From: Lake Orion Michigan
Part Throttle & Idle Stumble
Speed Density mode is when the engine's computer uses manifold vacuum, engine speed, and throttle position to control the air/fuel delivery to the engine. This is the method that was used in early computer controlled engines back in the 80s. Using Mass Airflow is a more accurate method for controlling the air/fuel delivery to the engine. The Corvette has the ability to use both methods. The Speed Density method is a backup to the preferred Mass Airflow method. The computer on the 1994 Vette will use the Mass Airflow method unless it detects a total failure of the Mass Airflow sensor. In my case, I was probably getting an intermittent airflow signal due to the wire being broken inside the insulation. The computer only checks for shorts to ground and no output of the sensor. By disconnecting the sensor, the computer defers to the Speed Density mode. Once the computer see that the airflow signal is back working, it will use the Mass Airflow method to control the engine. I hope this helps to clear up this discussion, for I have been fighting this problem for several years now.
