This is a strange one, and I'm not even sure I understand the symptoms entirely.
Our 2002 Malibu has felt down on power for a few months now. I've been trying to figure out what's going on by at least isolating "what" it's doing specifically, but even that has not been easy.
I came to the conclusion today that I think it's only down on power from about idle to ~3000 rpm. Above that, it begins pulling with normal gusto (or at least noticeably more). It drives like a vehicle with a lot of turbo lag, to me.
Additionally, the power delivery in that range under normal acceleration is almost "lumpy". It's almost a surge. Not to a degree that I think a passenger would question it, but it's noticeable.
I am not getting any codes. Fuel trims are no different than ever, about +2.34% to +3.12% long term on the highway at ~2000 rpm. Throttle position sensor readings are responding correctly. MAF values look realistic to me, up to about 150 g/s at WOT and near shift point. The timing seems to respond correctly.
Originally I thought it seemed just, down on power, but after flooring it a few times today I noticed that at almost all at once, nearly at 3000 rpm, it really starts pulling hard (okay, as hard as 170 hp will pull).
Any ideas? Things to check?
Our 2002 Malibu has felt down on power for a few months now. I've been trying to figure out what's going on by at least isolating "what" it's doing specifically, but even that has not been easy.
I came to the conclusion today that I think it's only down on power from about idle to ~3000 rpm. Above that, it begins pulling with normal gusto (or at least noticeably more). It drives like a vehicle with a lot of turbo lag, to me.
Additionally, the power delivery in that range under normal acceleration is almost "lumpy". It's almost a surge. Not to a degree that I think a passenger would question it, but it's noticeable.
I am not getting any codes. Fuel trims are no different than ever, about +2.34% to +3.12% long term on the highway at ~2000 rpm. Throttle position sensor readings are responding correctly. MAF values look realistic to me, up to about 150 g/s at WOT and near shift point. The timing seems to respond correctly.
Originally I thought it seemed just, down on power, but after flooring it a few times today I noticed that at almost all at once, nearly at 3000 rpm, it really starts pulling hard (okay, as hard as 170 hp will pull).
Any ideas? Things to check?