PJones96
Newbie
I've got a 96 C1500 with a 5.7vortec with 250k on the odometer. It seems like I have a ghost in the machine here. I need some help diagnosing an idle issue. The idle flutters intermittently. I wouldn't call it a surge because it's a very quick blip of 50-100rpm then it goes back to normal. That's a cold start without the ac running.
The real fun happens when I put it in drive. I have to hold the truck back with the brakes. When going down the road it feels like the truck wants to drive itself, meaning that it will gain speed without me using the accelerator. The pucker factor has gotten up there a couple times, not gonna lie. I can stop the truck and once the truck is stopped it eventually will idle down to a normal rpm. I took a short drive from a cold start. Put the truck in park and it revved to 3k. I had to put it in reverse to bring the rpm down low enough to shut it off. There's no CEL or pending codes.
I've replaced the MAP sensor, IAC and EGR valve. I've cleaned the mass air sensor. I realize I've described two different scenarios but I figured I would give as much info as possible. I'm trying to get this truck ready for my 16yo to drive but I can't give it to him like this....
The real fun happens when I put it in drive. I have to hold the truck back with the brakes. When going down the road it feels like the truck wants to drive itself, meaning that it will gain speed without me using the accelerator. The pucker factor has gotten up there a couple times, not gonna lie. I can stop the truck and once the truck is stopped it eventually will idle down to a normal rpm. I took a short drive from a cold start. Put the truck in park and it revved to 3k. I had to put it in reverse to bring the rpm down low enough to shut it off. There's no CEL or pending codes.
I've replaced the MAP sensor, IAC and EGR valve. I've cleaned the mass air sensor. I realize I've described two different scenarios but I figured I would give as much info as possible. I'm trying to get this truck ready for my 16yo to drive but I can't give it to him like this....