96 jetta idle problem

[dabatman99]

My Jetta when it is cold will idle rough, not smooth. When it warms up it smooths out a bit better. But when I turn on the AC, it gets rough again. Any ideas? O2 sensor, or something?

[goatmonkey]

check the standard stuff: electric grounds, plugs, wires, cap/rotor.

[MYVW]

Originally Posted by dabatman99

My Jetta when it is cold will idle rough, not smooth. When it warms up it smooths out a bit better. But when I turn on the AC, it gets rough again. Any ideas? O2 sensor, or something?

Had same exact issue on my 98 Jetta...replaced Throttle Body...problem solved. Not exactly what you want to hear since Throttle Body's not cheap, but it's amost certain to be your problem.


...Bob

[soccergk]

Originally Posted by MYVW

Had same exact issue on my 98 Jetta...replaced Throttle Body...problem solved. Not exactly what you want to hear since Throttle Body's not cheap, but it's amost certain to be your problem.


...Bob

You RARELY have to replace the TB. Usually it just needs a cleaning and you need to align it by putting the key in the on position until it stops whining. A rough idle on cold starts could be a number of things including a bad temp sensor. Check the normal things as stated above. Scan the car for codes.

[MYVW]

Originally Posted by soccergk

You RARELY have to replace the TB. Usually it just needs a cleaning and you need to align it by putting the key in the on position until it stops whining. A rough idle on cold starts could be a number of things including a bad temp sensor. Check the normal things as stated above. Scan the car for codes.

Throttle Body replace is not so rare. Yes, you can try cleaning(a I did), didn't solve the problem. Codes indicated intermittent throttle body. Proof is when replaced the TB eveything is now perfect. Sure try the simple stuff first, I can only tell you of my experinece with this idle issuse.