Bouncing/ Surging/ Cycling Idle 86 GXL NA
 

Bouncing/ Surging/ Cycling Idle 86 GXL NA

This problem has been plaguing me for a long time on and off. Before and after the installation of a FIPK kit by K&N and presliencer by Racing Beat. It cycles between 500-800 even after warm up. If I put my foot to the floor its holds a high rpm with a small amount of surging. I changed the tps with one I had off another engine and it fixed it for a few days now I’m back to square one. This is headache and is holding me back from enjoying my ride. If I could get a few suggestions in clear simple terms it'll help me out big time. Save my 7!
My Rx-7

Try putting a wire in the initial set jumper (by the leading coil)
That made mine quit doing that once after i adjusted the TPS - Use the method with the 2 lights too. Mine doesnt run right at 1k ohm.

Vacuum Leaks?
 

I thoroughly looked for vacuum leaks, just visually because the bouncing is so bad that the brake cleaner method won't help detect them. If during your replies you don't use any abbreviations’ that would be great. So I guess it is a vacuum leak around the injectors or the intake gasket but I’m not pulling it apart till I have the parts. I also have no air pump if that make any difference. Does anyone make an after market throttle positioning sensor that is more reliable? I can record a video of the engine in its surging mode if that would help to diagnose the problem. Theses are the potential problems I believe, Please add to it as you feel need be:

1. Faulty throttle positioning sensor
2. Faulty intake manifold gasket
3. Injector leakage
4.

If you have set the tps properly, then it is most likely a vacuum leak. It could also be a faulty idle solenoid. There is a troubleshooting section in the factory manual.
The injectors have rubber grommets that seal them to the engine block. Over time these can become very hard and start leaking. I guess if it were me, and I had tried everything else, I would buy new rubber for the injectors (there are three on each injector) a new intake manifold gasket and then I would pull the injectors. I would send them to www.rceng.com to have them rebuilt. Very cheap fix. Then reninstall everything and see what happens. Bottom line, it's cheap maintenance even if it turns out not to be your problem.

TPS misadjusted or bad
Intake vacuum leak
Throttle plates misadjusted / dirty TB

A basic acronyms list is in the FAQ stickies.
I'd suggest your go read it.


-Ted

Thanks
 

Thanks for the replies. I placed an order for an intake gasket kit today and will bring my injectors up to a local shop in a city near my back woods village. If anything else comes to mind please respond. I want my seven as reliable as possible. I’d like the explore the idea of third party replacement tps.