About my car problems.
 

So I purchased this 1991 RX7 convertible. It's got the n/a s5 motor. Well the car didnt run when I got it. Turns out it was flooded. I get a new battery and unflooded it and changed all my oil. (I premix) and the car runs good for about a month. I was driving down the highway doing 75 in 4th gear, then my motor sounded like it was only running on 1 rotor? Idk but when I gave it gas it would get louder but no power at all. So I shut it off and it will crank but wont start.

So please help me on this one. Thanks

why are you premixing with an Electronic OMP?
it either works or puts the car into limp mode..and if you are not racing the car then you are pretty well just wasting money.

You need to do a Compression check.Plain and simple.
The engine 'can just go'..it happens.

Mine went on the highway just getting up to speed..Poof..No warning,just crapped out and ran on one rotor.

Forgot to mention I dont have an OMP. The previous owner had a block off plate on it.
But would it still crank if it were gone?

S5's NEED the OMP hooked up unless the ECU has been changed to aftermarket

I bet your OMP is wired off to the side, and still crapped out

Just as I said..it either is working OR it puts the car into Limp mode.
You can have the OMP just hanging there BUT need it attached to the Electrical harness OR it goes into Limp mode.
It would also have to STILL WORK even though it is hanging OR ot would put the car into Limp mode.

SO...If the OMP went out on ya the car would go into Limp mode.....OR the engine crapped out and See my post above.(can we get a COMP check in Aisle
5????...)

the ONLY other way that the engine could run WITHOUT an OMP is that the ECU was replaced with the after market RTEK ECU which eliminates the OMP function from the map,allowing you to take the Omp OFF completely from the harness and then just premix.

And check for error codes as it is a simple process to do.