Well I thought I would ask you guys since you seem to know what you are talking about. I am having a problem with my car. It feels like some sort of fuel related problem but I'm not absouluty sure now. It started by just falling on its face when you would accelerate hard, like from a stoplight or low speed punch, the funny thing was that it only did this under 1/2 tank of fuel. So I started with the fuel filter, then I bought a tuned power fc because I thought that maby I was getting close to the edge with a dp, intake, and cb. oh, and at stock boost I do have a guage. So when I installed the computer I did plugs and wires. The same problem was there but the problem got worse. I then developed a high rpm stumble. It pull hard to about 6500 then just kind of quit pulling and you could feel it hesitating. So I thought that because I was running the injectors on the edge that may have been the problem. So pulled the injectors all 4, sent the primaries to be cleaned and flow tested and the secondaries to be changed to 1300's, also sent the computer back 2weeks after I bought it for retuning. While I had the intake off I cleaned up, removed the air port control, egr, ect and replaced every vacuume line. Still the same problem but a bit worse now it had began to do it say around 5500 to 6000 and now my o2 started reading lean. I also began running higher octane leaded fuel 112 octane, have a midpipe at this time. So now I just changed the fuel pump to the large nippondenso pump. Fells like the problem only got alittle worse. Now the car still idles ok and holds around the same vacuume as before, around 380-390 on the pfc. So my question is could I have a cracked apex seal and still idle ok but show up in the high rpms or could it be the fuel presure reg. maby even bad coils? Any help from the experienced would be appriciated, I've been chasing this problem since october. thanks
Nick

 

How about changing your spark plugs and wires. The spark plugs on the RX-7 doesn't last long at all. Also, try sending out your Power FC to XS instead of SR.

 

I already changed plugs and wires.

 

112 Octane should be a whole lot harder to ignite than regular pump gas.

You may need an ignition box.... MSD.. HKS Twin Power... the new box KD sells...


Leaded fuel will fudge an O2 sensor also...but you really only need the O2 sensor for idle... light throttle under 3500 RPM..... but I don't know what the PFC uses the O2 for...

Leaded fuel = heated 02 sensor

 

hey i really don't wanna sound stupid, but i always try the most simple ideas first, so could there be an possibillity that the fuel hose has some problem? maybe it's squeezed or so?

i don't think it's one of those "hi-tech-problems" cause u said "the funny thing was that it only did this under 1/2 tank of fuel" that's what makes me confused. is the gas pump not in the right posistion?

did anything happen to the car before it started to make that ?

 

sounds like your running excessiely rich....but if you already addressed that than check your coils