so I bought an 88 rx7 with a 1990 motor in it the motor has 4,000 miles on it after a rebuild from 12,500 miles the car has a high idle it idles at 2500 rpm it also has an 88 throttle body on it the 5th and 6th ports are open has a lightweight flywheel and racing beat exhaust he said he tried messing with the TPS but he said he no luck any help would be greatly appreciated

 

I saw it on craigslist and as soon as I saw 1990 motor in s4 I stayed away from it, mixing engine series is just asking for headaches. But check for vac leaks.

 

I've got an 88 w/ an S5 engine, Idles at 750, gets 22 mpg under mixed driving conditions (city & highway, AC almost always on) in FL. Best I've gotten is 25.5mpg...

That being said, you should be able to get it running smooth. Start here:

http://www.rotaryheads.com/PDF/2nd_g...systems_na.pdf

It's the emissions part of the FSM. Assuming you still have the rich/lean idle pot, and a good TPS, all other idle control, and NO sources of vac leak, it shouldn't be that hard. Wonder if the recirculation port on the center iron was blocked off? Does it have an S4 or S5 intake manifold?

 

has a s5 intake and s4 throttlebody