Has anybody experienced this before? I can't seem to find where this leak is coming from and every time it's like this the seals around the trunk seem to be dry. I sealed off the brake light at the rear of the deck lid but that did not improve the situation. This is also the second trunk lid this is happening on so I suspect it is related to the car. Any ideas or experience would be greatly appreciated.

 

It looks like condensate to me. Pull the rug out and check to see if it is wet underneath and check the drains.

 

x2. for condensation, and checking drains. You've probably got it under the bonnet too. Presume you can't garage it, only other thing is a car cover which provides some insulation for the metal surface exposed to the air/temperature changes. Or you could move ...

Nature, it's a wonderful thing.

 

I thought it looked like condensation as well but why wouldn't that happen in every car? also it is wet under the rug only after the trunk lid rains. It does not rain under the hood

 

It does happen in every Miata, that has water in the trunk.

tail light seals, hard top bolt seals, window seals, top seals, trunk seals, I’ve seen water get in the trunk from all these sources. Get a hose on trickle and put it all over the trunk while watching. Should easily drain away with leaking. If not,
you should spot the leak.

 

I had the same problem with my '90. I assumed it was the rain rail. As my top was complete ****, I replaced it and the rain rail a year or so ago, but the wet trunk remained. Turns out the tail light gaskets were rotted away. I purchased the replacements off ebay. One vendor sold a pair for $25 and free shipping, IIRC. It took longer to clean everything than it did to do the replacement. Problem solved.