My idle is around 600 when the car is in drive and sometimes it jumps up and down and makes my whole car shakes. it almost feels like a misfire but i know it isnt. I also know that it could be my Throttle Position Sensor, but my car isnt throwin any codes. Could my y pipe be be taking away back pressure and causes my idles drop? My dad wants to take my car to the shop, but i dont wanna spend all the money if it is a y pipe. So can a throttle position sensor be bad without throwing codes?

 

you may want to check out your IACV (idle air control valve) This valve adjusts your idle speed. Sometimes when the valve sticks, it may cause some rough idling. The IACV is located next to the TPS.

 

Clean the intake and the idle air control valve. If that doesn't stabalize your idle then I'd definately replace the TPS. Those issues you describe are very typicle of a TPS failure or just out of spec, yet functioning so your not 'yet' getting a code for it.

 

i think you should check the coils a know issue on our cars specially 99's also check IACV , fuel filter ,air filter,plugs and like you said TPS but check for the obvious first.

 

thanks guys, will do this weekend.