bubba24

Okay when the car is cold or first started it runs smooth, but once the car is warmed up and is idling at 600 rpm A4 it runs rough and shaky. If you give the throttle quick snap it hesitates and just shakes. But if you say bring the throttle up too 1500 and snap the engine takes off and doesnt hesitate just revs smoothly.

Now i have changed coil, plugs, plug wires,cleaned Maf, checked vacuum leaks, I have air and egr deleted properly plugged and not leaking. Even new o2 and they are running smoothly.


Thanks for any help

Formula350

iTrader: (3)

Throttle Position Sensor or the Idle Air Control. TPS reading bad volts at idle or the IAC is sticking. Unplug one and rev it up, if things change, decent chance that sensor is OK, do the same for the other. If nothing changes for EITHER, well both MIGHT be junk

I don't like IACs Seem so darned worthless lol

bubba24

yah i cleaned out the iac so it cant be sticking now but there is still no change. And the tps I unplugged it and the throttle started to speed up and plus i used a multimeter and it was good for volts even at wot it was good. But im beginning to think it must be some sensor when the car gets warmer that makes the stumble when I snap the throttle cause it doesnt do it when I first start the car, just after a while it will do it.

bubba24

okay i also noticed whenever the engine shakes at idle the lights flicker and I can see the volts gauge move. This might narrow it down now.