I got a '92 bonneville SE with 440000kms on it, whenver I'm driving and I kick it down as soon as it hits 4800rpms give or take the check gauges like starts flashing, not the service engine light or nothing, all the guages stay in normal. any ideas what it could be? someone suggested that maybe the timing is out, or a valve of some sort at that rpms gets stuck open. any help would be appreciated.

My guess is you're redlining the engine. The "Check Gauges" warning will trigger when any gauge goes out of range, not just when you're low on fuel. (You may not have the needle actually into the red zone of the tach, but the ECM may choose to trigger the warning even if the tach is reading something slightly lower.)

its never done that before ever when the rpms have hit that high, would that mean maybe the ECM is starting to die?

I kind of doubt that. You're not getting error codes; you're getting a warning about one or more gauges. It'* hard to say for sure, and possibly you've got some transitory thing that'* gone away by the time you look down; e.g. maybe you're revving so high that your oil pump is cavitating or starving, and you have a temporary loss of oil pressure that recovers shortly thereafter. I don't recall if you've got a supercharged engine, but it could be overboosting and opening a wastegate.

But all that aside, you might want to take these occasional warnings as a hint that something far worse is not far off: by your own description, you have a high-mileage engine that you are pushing really hard, and it sounds like something is about to break here. When you approach redline, you're out of the best part of the engine'* power curve anyway, and are producing more noise than acceleration. It'* better to get the upshift and roll on the power at a lower rpm.

For example, a standing start in my SSEi will let me run the rpms way high before it upshifts to Second, but acceleration is nothing special. On the other hand, if I hold back a little on the acceleration until it goes to Second, and _then_ roll onto the gas, the g-force is definitely higher and I know I'm getting more bang for the buck.