1993 Chevy 1/2 ton, 5.7 L, 4 WD, 5spd, 167,000 miles:
Once the truck reaches operating temperature it can't maintain an idle and dies. At steady highway speeds, there is a sudden loss of power.
Two different shops have not been able to correct the problem. I was told there were no vacuum leaks on top. They said the engine was in good shape. One shop adjusted the new IAC valve I had installed. The shops said all sensors appear to be properly connected and functioning. A new mass airflow sensor didn't change condition. The intake manifold gaskets were replaced and timing reset. In between shop visits I replaced the stock computer box with a remanufactured unit with no change in problem. Since coming back from the shop, the service engine soon light has NOT come on despite the problems.
Note: The vehicle previously had a Vortech supercharger installed. All supercharger components have been removed and returned back to stock form with the exception of the additional inline fuel pump. I had earlier replaced the stock TBI with a rebuild ported Turbo City version. I also have tri-y headers (with O2 sensor), replacement cat, and low restriction exhaust currently installed.
Once the truck reaches operating temperature it can't maintain an idle and dies. At steady highway speeds, there is a sudden loss of power.
Two different shops have not been able to correct the problem. I was told there were no vacuum leaks on top. They said the engine was in good shape. One shop adjusted the new IAC valve I had installed. The shops said all sensors appear to be properly connected and functioning. A new mass airflow sensor didn't change condition. The intake manifold gaskets were replaced and timing reset. In between shop visits I replaced the stock computer box with a remanufactured unit with no change in problem. Since coming back from the shop, the service engine soon light has NOT come on despite the problems.
Note: The vehicle previously had a Vortech supercharger installed. All supercharger components have been removed and returned back to stock form with the exception of the additional inline fuel pump. I had earlier replaced the stock TBI with a rebuild ported Turbo City version. I also have tri-y headers (with O2 sensor), replacement cat, and low restriction exhaust currently installed.
Aug 23, 2007 at 9:21 AM