Usually that's not a fuel supply problem, at least not directly. This is more typical of an electrical problem. More specifically, look for loose or corroded terminals in an electrical connector or wires that are rubbed through. The connectors will be between the body and engine where the rocking of the engine tugs on them. The wires often rub through on the body, also from the engine rocking, or they can by laying on a sharp metal bracket on the engine.
If the problem is related to a sensor, there may be a diagnostic fault code stored in the Engine Computer although GM has an unusual strategy where the computer watches a problem for a while before it sets a code. Check for codes anyway, even if the Check Engine light didn't turn on. The light is only required to turn on when the detected problem could have an adverse effect on tail pipe emissions.
If there are no fault codes, the best approach is to use a scanner that can display live data on a test drive. Many scanners have a record feature that will record sensor information when the problem occurs. Because the data travels through the scanner's memory, the recording actually starts a couple of seconds before the button is pressed.
If the engine sputters as it dies over a period of a few seconds, fuel pressure may be dropping off. If it dies instantly, similar to turning the ignition switch off, a loss of spark problem is more likely.
Thursday, June 2nd, 2011 AT 2:16 AM