At full throttle in gear my s4 88 rx7 has little power till 4000 then it struggle rev to any higher, but at quarter throttle it smoothly revs till redline and in neutral or with clutch in it revs instantly to redline

 

The hiccup at 4000rpm is the notorious "3800rpm hesitation". Do some searching and you'll see how common it is.

Normally it's caused by bad grounds, but you mention being down on power across the board. This implies to me that you are probably running lean, which compounds with the lean spike at 3800rpm when the secondary injectors come online.

I would start by checking for vacuum leaks, as that is the most likely cause. Checking and cleaning all the grounds also wouldn't hurt.

One last thing to mention is that these cars (NA anyways) don't really make much power until 4000rpm anyways. It shouldn't be "slow" below 4000, but it doesn't have the same torque as other cars do. 4000-7000 is where the fun happens in Rx7s.

 

I checked and cleaned my grounds, I also added an extra ground from the engine to the the firewall, I started to test sensors and started with my throttle position sensor, at full open between a and b i get 1.97k ohms, at closed I get 1.6k ohms, between b and c i get 1.97k ohms.
About 900 ohms from a c. I'm gonna test my secondary injectors tomorrow and my afm

 

Your TPS readings look off. You should be seeing 5k ohms at some points. See below from fsm.
Kind of goes inline with the running lean WondrousBread is saying. At full open you should be at 5k, but you're only seeing 1.9k. So your ECU isn't giving correct fuel amount at fuel open.

EDIT: Also " ...but at quarter throttle it smoothly revs till redline..." , at quarter throttle it is possible your TPS just so happens to be near the expected ohm value and can climb revs as a result. If that makes sense.

 

Is timing confirmed?

 

Did you figure out the problem?

 

Let me know the issue if you've found it please!

 

So I believe it was a vacuum leak near the 5th 6th port actuators, I can't confirm cause I blew my pilot bearing and can't recreate the issue till I get that fixed, But that seemed to have solved the bad idle with tps