Hi all recently my scoob has devoloped quite a lumpy idle like the car is shaking side to side, and iv also noticed that my turbo gauge is fluctuating while idleing also, iv checked to see if the ht leads were loose, and checked all the pipes to see if anything was loose, but i still cant diagnose what the problem seems to be? Anyone have any ideas?????

p.s MY97 STI Vers: 3

 

Could be a faulty air flow meter bud! I'm sure someone in the know will either back me up or correct me!

Hope this helps

 

It might be the airflow meter, but there are plenty of other potential causes.

The AFM can be ruled out fairly authoritatively and simply by getting the engine fully warmed, switching off, unplugging the MAF and then starting back up. Don't drive it, but evaluate the idle. If your problem has completely disappeared then a new airflow meter is in order. If the issue is the same or worse, switch off, plug the sensor back in and start looking elsewhere.

Do not at any point disconnect the airflow meter with the engine running, it won't tell you anything useful, despite what some on here may misguidedly think.

Also, if the idle is odd, how is driving performance? Any power loss, or all bang-on normal?

Have you looked for and ruled out an air leak in the idle air control system, btw? What about taking the plugs out and examining them, or running a comp test?

 

performance is still top notch, it has seemed a bit sluggish recently but i think thats due to the warm weather, where is the idle air control system sp??

 

Seems to me to be a small airleak.