I have a 2020 Silverado LTZ Z71 with the LM2 engine.
A couple of weeks ago I actually took it out and drove a forest service road that needed high ground clearance and 4-wheel low in order to negotiate some rocky areas. I was in 4-wheel low and geared down to L1. As I'm walking over the rocks at idle (300 RPM), everything is fine. As I'm tip-toeing through the goofy terrain, I would work the throttle up and down. If I touch the throttle and the RPM slowly increases to 500-600 RPM, the truck responds accordingly. However, when I creeped the RPM up into the 800-900 RPM range, all of a sudden, the RPM jumped up to 1,500 RPM on its own (not good when you're trying to negotiate dicey terrain)! I took my foot off the throttle and the engine continued at 1,500 RPM. It took some aggressive braking to slow the engine down. Once it got below about 1,000 RPM, it dropped back down to idle. This behavior was very consistent. It didn't matter if I was going up hill or down, forward or reverse. The same thing happened. I haven't been able to reproduce the problem in 4-wheel high or 2-wheel drive. Anyone have any ideas on what's going on?
I have a theory (no facts to back it up) that the turbo is doing nothing at idle and low RPM, but, for some reason it's kicking in once engine RPM hits about 1,000.
Thanks.
A couple of weeks ago I actually took it out and drove a forest service road that needed high ground clearance and 4-wheel low in order to negotiate some rocky areas. I was in 4-wheel low and geared down to L1. As I'm walking over the rocks at idle (300 RPM), everything is fine. As I'm tip-toeing through the goofy terrain, I would work the throttle up and down. If I touch the throttle and the RPM slowly increases to 500-600 RPM, the truck responds accordingly. However, when I creeped the RPM up into the 800-900 RPM range, all of a sudden, the RPM jumped up to 1,500 RPM on its own (not good when you're trying to negotiate dicey terrain)! I took my foot off the throttle and the engine continued at 1,500 RPM. It took some aggressive braking to slow the engine down. Once it got below about 1,000 RPM, it dropped back down to idle. This behavior was very consistent. It didn't matter if I was going up hill or down, forward or reverse. The same thing happened. I haven't been able to reproduce the problem in 4-wheel high or 2-wheel drive. Anyone have any ideas on what's going on?
I have a theory (no facts to back it up) that the turbo is doing nothing at idle and low RPM, but, for some reason it's kicking in once engine RPM hits about 1,000.
Thanks.
Last edited: