Okay heres the problem, Upon start up cold it idles up and down, 1k to 1.5k. Then as it warms up no problem but I have to adjust tps up to idle right but at 1.5k. After this if you give it a little gas slowy going up, it goes up and down. This sounds like tps but Ive changed it out with 3 known working tps. Checked timing and vacum leaks good. Could it be the injectors? Also my setup is kinda wierd, Im using a n336 ecu, 326 pressure sensor, the motor is an s5 na motor, all this in a 88 T2. Im also thinking it could be the ecu pinouts maybe different. More research but until then, let me know what you guys think.

 

Don't know. I hope somebody does, because my 88 TII does the same thing. Kinda annoying.

 

Adjust the tps so the resistance between the top, and the bottom right connector(when looking at the prongs) is 1028ohms, and check and make sure 1 connector has no continuity and the other does on the tps adjustment light connector, problem should go away, did on my car.

 

Everybody zeroes in so hard on the TPS as the cause of hunting idle. The first step is to get the TPS adjusted correctly. But then you have to adjust the idle. Ground (or short for S4's) the initial set connector and make sure idle is at 750 for a fully warmed up engine.

 

Ive set the tps, fully warmed, connecter, etc. Tested it for any skips, all good. I cant get the idle down to 750, vacum leak right?? Tested for leaks and no leaks found. Still scratching my head. It drives good all through the rpm, just at idle and when you blip the throttle a little. Could it be the thermowax warm up messing it up?

 

My problem with high idle is that I didn't adjust the variable resistor. When I removed my emissions devices and such, the car was running lean at idle and causing it to idle poor. After adjusting the variable resistor and richening things up, the car idles perfectly at 800 RPMs with no idle up or down. It's not always the TPS causing things to be bad.

 

^^ tried that already but no luck too.

 

Well, I had the walboro fuel pump swapped out with the stocker, and it helped out a whole lot!!! Set everything to spec and running a lot smoother. I guess the higher flow was messing with the fpr.

 

Lower your base idle with the BISS screw, located on the back side of the throttle body. Re-adjust TPS and BAC (fine idle adjust) screws afterwards.