Throttle oddities.

[JwUoNoG]

I noticed while sitting in my car, that if I rest my foot on the gas very lightly, the RPMs drop. My S-AFC says the throttle goes up, but the RPMs still drop.

Also, my throttle won't go any lower than 5%, is that normal? I'm assuming it is, the throttle has to be open at least a little bit during idle.

 

[doodie]

I'm not sure why its dropping when your stepping on the gas but your SAFC shouldn't show 5% If its showing 5% then get out of the car and go under the hood and try to close the throttle a little bit. Go back inside of the car to see if it says 0% If it does, than go adjust your thorttle cable. There should be 2 10mm bolts holding the throttle cable onto your intake manifold. Loosen those two bolts and push the cable to the left very little. By doing this, your giving your throttle a little bit more slack and it will be able to close fully.

If you have cruise control, I would just yank it out and throw in a non-cruise cable. Thats what I did since the cruise was pulling my throttle open at idle and I was getting a 3% throttle and 2k idle.

 

[GTM]

...
Also, my throttle won't go any lower than 5%, is that normal? I'm assuming it is, the throttle has to be open at least a little bit during idle.

No, not normal. Previous posts had the obvious things. Worn throttle shaft and/or bushings, bend or damaged throttle plate.

At idle air is being fed through the air passage along with the passage which is accuratly trimmed with the biss screw. My experience has found that many makers have this designed to be very close to 3 turns out but I've seen other reports with larger numbers. If you have not tampered with this then you can count the number of turns to screw it down until it's lightly on it's seat. This way you will know how to get back to the original setting. You can try somewhere between 2-1/2 - 3-1/2 and see if that improves anything, if not return to original setting and look for other problems.

Cheers,
GTM

 

[oddrob]

You can also use the AFC to check the voltage on your TPS to make sure its within the proper range and adjusted correctly. Sometimes the AFC throttle settings have to be set as well. You can follow directions in your manual for this.