OK, the car is a 1990 NA. And what it does is once it warms up, and if it is in netral/park (it's an automagic....) the engine will every now, and then. Just start reving it's self. It's just annoying, I having noticed anything else wrong, but the RPM's will just jump, up and down about 250-500 RPM's. But if you get out and hold the main TPS in, it stops. Does it just need adjusted? If so, is the S5 TPS any different than adjusting the S4 TPS?



Or is it something else??? https://www.nopistons.com/forums/pub...DIR#>/ohmy.png

It might be your Water-Temperature Sensor actually. On my '86 Corolla GT-S when I first bought it, the idle was NEVER constant because the sensor was broken and the car never knew what temperature it was. Check yours, and see if it works. A replacement was only $10 at Autozone. It's worth trying. Once I replaced the sensor, the car idled fine, therefore fixing the problem.

Anyone else have any idea's?



I would go down and buy a new one, but if it didn't fix it I would kick my self for wasting $20 bucks on it, when that's not the problem.....



I might do it anyways https://www.nopistons.com/forums/pub...#>/biggrin.png But my temp sensor works fine. It always parks it's self right in the middle of the guage. Maybe it's broken https://www.nopistons.com/forums/pub...IR#>/dunno.gif

mine has just started doing that too

is yours auto also shane?



my automatic did that, but my 5 speed never did.

yeah it is

It's not the tranny, because I have had a manual that did it...



But the automatic doesn't do it in gear...

Set the TPS anyways. It doesn't take long.



Are you sure there isn't a vac leak or something somewhere?

set the tps and idle speed first before you do anything else

I don't want to screw with the idle... It's bad to https://www.nopistons.com/forums/pub...1047683358.gif



It idles at about 1500.... But when it is in drive, or any other of the automagic gears, it sits perfect at 750! So it's fine with me, I'm not out of gear that much.



Also is it the BAC valve that makes the engine RPM go up when you put it in gear? I'm thinking that is for the AC, but it may serve a dual purpose on the automatic... But one of the valve's must be stuck open for it to idle this high out of gear.





And I'll go tinker with the TPS https://www.nopistons.com/forums/pub...#>/biggrin.png