Just had my 09 into the dealership for a slow cranking issue. At first it was only happening after sitting overnight but it got progressively worse over the course of about a week. I thought it was just the battery, which it was partially, but the dealership said it was still slow cranking even after replacing the battery. They decarbed it and that fixed it.

I do know this, my car is running noticeably better than it has for quite awhile. I think the problem had built so slowly that I didn't notice the loss in performance. I haven't been able to track my car at all recently, probably in over 8 months, which I think goes a long way to keeping these motors decarbed and healthy. I do redline quite often, but apparently that wasn't cutting it.

So I think I will start sea-foaming myself, pretty frequently. Just thought I would share this as I know some people here think seafoam isn't necessary.

Edit: I'm just under 42k miles now btw.

 

the only thing i can see seafoam doign to help cranking is cleaning your spark plugs.

Other than that i really dont see what it could have done to help cranking.

 

Just some info to consider:
https://www.rx8club.com/series-i-tec...r-pics-241867/

 

Seafoam is the same stuff the dealer uses to decarb right?

 

Dealer use the "zoom zoom cleaner", but they both achieve the same goal.
Some members don't believe in decarb, and some do.
Personally I had good experiences with decarb.

 

I should probably add the dealer replaced the plugs too, but they were NOT the issue as they had less than 2k miles on them.