Hacksterbaby
New Member
Hey all,
92 LS automatic, 208K. Engine well maintained, purrs like a kitten. 100-mile daily round trip commute. It's recently started stumbling when it gets up to highway speeds (>60mph; usually run 75-80). At first I thought it was the engine missing, but that didn't seem to make sense since it idles fine, accelerates and shifts through all the gears fine, etc., so that seems to rule out fuel pump, fuel filter, timing, vacuum leaks, etc. Once it starts the stumble is fairly continuous and ranges from real light to real noticeable.
It appears that it may be confined to 4th gear. Trans fluid level is fine, nice bright red. The only tranny-related part covered in the Haynes book that I'm *not* sure that it's *not* is the vacuum modulator, and I'm not sure what that is, what it does, or what it looks like (no pics in the book). Is this something that *might* be the problem, and if so, any help on finding/replacing it? Or any other thoughts on what it might be, if not the tranny? Any and all ideas appreciated-- thanks.
92 LS automatic, 208K. Engine well maintained, purrs like a kitten. 100-mile daily round trip commute. It's recently started stumbling when it gets up to highway speeds (>60mph; usually run 75-80). At first I thought it was the engine missing, but that didn't seem to make sense since it idles fine, accelerates and shifts through all the gears fine, etc., so that seems to rule out fuel pump, fuel filter, timing, vacuum leaks, etc. Once it starts the stumble is fairly continuous and ranges from real light to real noticeable.
It appears that it may be confined to 4th gear. Trans fluid level is fine, nice bright red. The only tranny-related part covered in the Haynes book that I'm *not* sure that it's *not* is the vacuum modulator, and I'm not sure what that is, what it does, or what it looks like (no pics in the book). Is this something that *might* be the problem, and if so, any help on finding/replacing it? Or any other thoughts on what it might be, if not the tranny? Any and all ideas appreciated-- thanks.