I did a diagnostic check and came up with these results:

1 long flash 2 short flashes
1 long 3 short
1 long 7 short
1 long 8 short

my RX-7 mfg. date is 7/89 (making it a 90?) 13B non turbo, Auto.
I think its got something to do with the idle sensors. I have also been having problems with the AC choking the engine when at idle speed. I used the manual to set the TPS at 1000 Ohms (at normal operating temperature) and the check engine light has stayed off since. The idle is still a little rough and the AC nearly kills the engine as soon as I hit the button. But I guess what I really want to know is what those codes mean.

 

89-91s are all S5, half years are hence independant.

Code 12: TPS Full range. You'll want to fix this. Grab a multimeter and adjust per RETed's website. His Howto is S4 specific, but use the same TPS leads and his method works fine. When the Full TPS goes out of range, it defaults to WOT, which makes your car run super hella rich. This will make yoru car run like ****. But it may not happen all the time.

Code 13: Pressure sensor (intake). Meh, I get this all the time. A midly modified engine can trip this sensor out of range. When the sensor goes out of range, the ECU substitues with 760mmHG (1ATM). You'll want to grab a copy of the FSM, vac gun, and multimeter to test to make sure the sensor isn't dieing though.

Code 17: Feedback system. Meh, you're 02 sensor is probably disconnected or shot. This isn't terrible, but it does keep the ECU from letting the fuel system go into closed loop. Closed loop will save you 5-6 (or more) MPG at cruising speeds.

Code 18: TPS Narrow range. Welp, the fact that the narrow TPS tripped aswell as the full range means that its probably not the sensors, but just the adjustment. Grab RETeds howtow, a multimeter, and about a half hour if you've never done it before.


EDIT: I see you already adjusted the TPS. Grab an analog multimeter and check for spikes now that you have it set. A quick spike in the sensor can screw with the ECU temporarily and trip the code. As for the AC killing the engine, the BAC valve comes to mind. It could be dirty and all crapping out. Heres how to clean it: http://www.1300cc.com/howto/how2/bac.htm. If you have an n/a, the BAC is under the TB. Otherwise its right on the manny on a TII.

 

Awsome info. thanks... By the way I cleaned out and tested the BAC valve. Everything checked out. My problem still exists. What I have just noticed is that the idle will pulse between 700 and 1500 Rpm. until I depress the brake pedal fully. Then it sits rock solid at 900 RPM (in Park)For this reason I suspect a Leaking brake booster or shot check valve. Oh well, on to my next project.