GSL SE Randomly won't start without starting fluid.
 

I've owned two FC Rx7's one of them a beast of a turbo car and yet I am getting my butt kicked by my relatively new (to me) GSL SE. It drove fine for awhile then after about 6 months of driving, it got acquired a seemingly intermittent bad miss fire at part throttle. Now that has gotten progressively worse and all of a sudden now it randomly won't start at all unless a give it a shot of starting fluid. This leaves me to believe that it is in fact not flooding as adding starting fluid (more fuel) to the mix wouldn't help it start.

Any ideas what it could be? I adjusted the TPS correctly but that didn't fix either of the problems. I'm thinking it could be the coolant temperature sensor? If so which one does the ecu read as there are multiple coolant temperature sensors.

You have owned several rx-7s and I don't want to insult your intelligence, but have you checked for vacuum leaks? My GSL-SE behaved similarly (albeit after sitting under a tree for years). I did a ton of diagnostic work, turned out the intake wasn't sealing properly were it connects in the middle. I wrapped duct tape around it and boom problem solved.

on to more serious issues:
-Bad water seal could display these symptoms. Maybe not the partial throttle misfire, but certainly the hard start.

-I have a feeling people will say stuck injector. I have never experienced this myself, but it seems to be common and could manifest itself in your symptoms.

As a general note: Don't rule out fuel flooding because starting fluid starts the car. Starter fluid will get your rotary going whether it's flooded with water, fuel, mouse turds, too much air, not enough air etc. Believe me, I love starter fluid, but it has taken me down the wrong path many a time.

Have you checked the fuel pump? Could have been starting to go and then quit on you

Coolant temp sensor shouldn't prevent it from at least firing if it's getting the right amount of fuel and air.

Also worth checking the wiring harness that runs under the Upper Intake Manifold and carries the Injector pigtail leads. With the engine running, or part throttle, grab that harness and push, pull, etc to be sure its not an intermittent lead. If it drops out of throttle, you may have found your problem. Same thing for the temp sensor at the back of the waterpump which is used for cold start ECU map.

other than this, does it hot and cold starg as expected? It should have specific timings like 30s for high idle rev during cold start with cold outside air temp, along with a clutch in vs. clutch out idle speed adjustment.