I have had this car for about a month and a half now (many issues). It is a 1989 GXL NA 5spd. It has cat-back exhaust and intake (thats it for engine work). When i accellerate i get the RPM's up to 6500 RPM's..... and once that happens the car has an insane amount of power loss and crawls up the tachometer after 6500.

I changed the plugs and wires, runs a bit smoother and stronger but still, 6500 RPM comes up and its like trying to get a fat kid to sprint up a hill after a carrot.
I looked at the battery connections and grounds, wow they were bad, so i re-did the grounds and positive wires, still same thing.
Could it be the secondary injectors?
or could it be a timing problem?

The car doesnt quite pop when its running, (sound is in the exhaust) its kind of like a palunk almost a pop, i know it has an exhaust leak, could this also effect the way it runs at the higher RPM's?

 

If the secondaries are not functioning, it's possible to make it to about ~6k RPM before you run into a lean hesitation. There's a thread floating around here where someone had this exact problem, and it turned out the secondary injectors were not working. Check to see if you have 12V on the secondaries either at the ECU or at the plugs.

 

i think you mean this one:

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/power-drop-noticeable-hesitation-issue-high-6300-rpm-802779/

 

i had a similar problem on my s4 t2, it turned out to be a faulty map sensor.

 

Thanks Karack, i looked at all my wiring and there are some wires that are corroded and have deposits and bad insulation, thats probably a huge problem. Thanks for the link very helpful.

 

Update.... Ok. Re wired some bad connections to secondary fuel injectors and now it intermitantly or randomly will run smooth through 6500 rpm. When it does not rev through it smells like its running rich. Could it be my 6th port sleeves not opening? Are they controlled electonically? Or are they controlled by vacuum?

 

I had a similer problem with 87 na. it wouldnt rev past 5500rpms. I found that there were alot of vaccum lines disconected and not plugged. that fixed the prblem that time. and more recently it started acting up again and that was becasue my trailing ignition coil for the front rotor went bad and i wasnt getting spark. when the coiul went out i was getting really bad backfires, surging around and after 4000rpms. hope you find this helpful and good luck with ur rx =)

 

some vacuum lines were old and i replaced them....lots of them were worn and one was cracked bad.....new ones......lubed up the 5th and 6th port actuators......i do have an exhaust leak i need to fix....i read about the port actuators and it seams like they also need back pressure from the exhaust system to work properly?

 

You have an S5 so the 5/6 ports are actuated by the air pump not the exhaust.