[M3 the dream]

Question, about the car hopefully someone can give me a place to start
as Im driving over a bumpy road or any pot hole pretty much anything to jerk the car the gas gauge drops to zero radio shuts off engine revs drop and all of this happens in less than a second and the car is normal, also have realized if i brake hard over uneven road almost 100% of the time this will happen, and then once again the car is fine after the engine corrects itself by that i mean, after the second of revs dropping the revs go up and down till the car is stable again, If you have any ideas please shoot them out, My opinion is it could be loose grounds (as this was in the past) but the car hasn't done it for months and they are all really tight or a problem with the fuel system

[enderw88]

What about the lights? Do the head lights dim, the interior lights as well? Is it essentially EVERY electrical item?

[M3 the dream]

thats a good question about the headlights will have look out for that when driving at night also, that made me think of another thing at night with the center interior light to the middle position or auto position under hard braking that lights turns on and then off a few seconds later, ill have to be on the lookout for every electrical item when this happens again, narrow the problem

[DLite]

First easy check would be the ground straps and B+ junction point (the + jump connector) in the engine compartment. Make sure all those connections are clean and tight.

[98///M3]

First things first. Use your period key. I know it's overrated, but it will make your posts vastly more intelligible.

Second: you have an electrical issue, probably the type of problem where every little detail is pertinent. Tell us everything, we won't make (much) fun.

Third: the fact that your radio goes off and your fuel gauge drops tells me it's a main ground, not power connection. If your car is in gear, then the revs are not dropping, the tach is losing power and you are reading it as the 'revs' dropping.

Check your grounds. Get the ETM, if you don't have one already. You can find the locations in there. At any rate, Let us know.

[enderw88]

Originally Posted by DLite

First easy check would be the ground straps and B+ junction point (the + jump connector) in the engine compartment. Make sure all those connections are clean and tight.

This. And remember just because you think your grounds were tight yesterday doesn't mean they are today. "Old German Sports Car"

[cstern]

I had a similar problem. Hit a hard bump and the entire car would cut out for maybe a second, including the engine, but come right back. As strange as it is, a tail light was the problem, or at least the water trapped in it and behind it was.

My passenger tail stopped working shortly after this problem started. The entire back of the light was rusted and I found water trapped in the body behind it. I dried everything up and replaced the tail and no more problem since.

[cmcon98]

It sounds pretty elementary, and you've probably checked, but battery connections. It has to be electrical if multiple electrical items go dead at the same time the engine cuts out for a moment.

[M3 the dream]

thanks alot so far lots and lots of great ideas for me to check out over the next days, i have alot of checking to do, also was driving today, and thought of another possible thing that is causing this, opinions on this, the screw that holds the battery in place broke so the battery has a bit of wiggle room, i remember messing with the battery and the terminal closest to the frame of the car in the compartment touched the metal and sparked, when the car was off, if this happened when the car is on could this possibly short the car out for that split second, cause under hard braking the battery could move forward and hit, not a electrical scientist just curious, once again thanks for the ideas and opinions really helpful

[M3 the dream]

Thanks a lot so far lots and lots of great ideas for me to check out over the next days. I have a lot of checking to do. Was driving today and thought of another possible thing that is causing this problem. The screw that holds the battery in place broke so the battery has a bit of wiggle room. I remember messing with the battery before and the terminal closest to the frame of the car in the compartment touched the metal and sparked when the car was off. If this happened when the car is on could this possibly short the car out for that split second. Under hard braking the battery could move forward and hit. Not a electrical scientist just curious. Once again thanks for the ideas and opinions really helpful. (updated grammatically correct version and not me rambling ideas with no end)