GMnutbag
Newbie
I have a 1997 Cheyenne cab & chassis, C3500, 5.7L vortec, 2WRD, 2DR, auto trans, engine code "R"
I bought the truck over 10 years ago with a blown engine. The odometer shows 156K. The seller assured me that the tranny was replace 12K ago when I bought it. I finally got time to work on it. I put in a remanufactured engine. I also replaced EVERYTHING with the engine. It starts up fine, runs about 2K rpm for about 8 seconds or so. But when the idle comes down it immediately starts to surge in RPM's till it dies. If I unplug the mass air flow sensor it seems to run perfectly. I can then plug the amf sensor back in and it continues to run fine. If you shut it down it just repeats the problem. I have the original maf sensor and 2 brand new ones and it does the same thing no matter which one is hooked up. Here's a list of all the new things besides the engine that I've replaced more than once trying to figure this out. It has brand new air intake temp sensor, mass air flow sensor, idle air control sensor, throttle position sensor, MAP sensor, EVAP solenoid, EVAP purge valve switch, upper intake manifold (plastic), fuel pump, fuel tank, fuel filter, air filter, crankshaft position sensor, camshaft position sensor, oil pressure switch/sensor, coolant temp sensor, radiator, main computer, all fuses are good and correct, distributor, coil, ignition control module, spark plugs & wires, EGR valve, fuel spider injector system (located in upper intake manifold), anti-knock sensor, intake manifold to head gaskets, fuel pressure regulator, and no vacuum leak of any kind. Even if I've missed something in this blog, I can assure you that it's been replaced at least twice. I'm just at a dead end for something to look at or check out that could cause this problem. If you've taken the time to read this story, I thank you and welcome any insight you may have. Thanking you in advance.
I bought the truck over 10 years ago with a blown engine. The odometer shows 156K. The seller assured me that the tranny was replace 12K ago when I bought it. I finally got time to work on it. I put in a remanufactured engine. I also replaced EVERYTHING with the engine. It starts up fine, runs about 2K rpm for about 8 seconds or so. But when the idle comes down it immediately starts to surge in RPM's till it dies. If I unplug the mass air flow sensor it seems to run perfectly. I can then plug the amf sensor back in and it continues to run fine. If you shut it down it just repeats the problem. I have the original maf sensor and 2 brand new ones and it does the same thing no matter which one is hooked up. Here's a list of all the new things besides the engine that I've replaced more than once trying to figure this out. It has brand new air intake temp sensor, mass air flow sensor, idle air control sensor, throttle position sensor, MAP sensor, EVAP solenoid, EVAP purge valve switch, upper intake manifold (plastic), fuel pump, fuel tank, fuel filter, air filter, crankshaft position sensor, camshaft position sensor, oil pressure switch/sensor, coolant temp sensor, radiator, main computer, all fuses are good and correct, distributor, coil, ignition control module, spark plugs & wires, EGR valve, fuel spider injector system (located in upper intake manifold), anti-knock sensor, intake manifold to head gaskets, fuel pressure regulator, and no vacuum leak of any kind. Even if I've missed something in this blog, I can assure you that it's been replaced at least twice. I'm just at a dead end for something to look at or check out that could cause this problem. If you've taken the time to read this story, I thank you and welcome any insight you may have. Thanking you in advance.