Car:1998 Evo 5 (un-modified)

Problem: While driving at a constant speed as soon as you flick aircon on the engine starts jerking/stuttering . Does not happen while accelerating/de-accelerating or while aircon is not running. (there is no change in rev counter while/boost gauge with this is happening.

Full story: Driving one day and slowly car electrics started to die, first stereo then window wipers rev counter etc.... until eventually car died. Would then not start. Was able to jump start but same problems happened as i was arriving back home.
Replaced with a new battery and everything seemed all good until this current problem was noticed. Since then i have had a full service done that included a couple of cracks in exhaust manifold welded new gaskets etc... and a new set of spark plugs.
(this may not be relevant but may help diagnose)
Problem still present.

Any help ideas much appreciated! or even where to start. should i go to an auto electrical repair shop or a mechanic?

 

Do you have the a/c on I get it too. I think this is normal because there is more strain on the motor due to extra loads on the belt and pulleys.

 

Could it be your alternator?

 

This is not normal, never had an issue before with aircon running. You can feel the whole car lurch as the engine stutters

 

I second the alternator. You need to check voltage as the car is idling. Then turn on accessories, such as the a/c, radio, lights, etc. GL.

 

Ok sounds good, will test the voltage tonight and see what it's reading. Thanks

 

Sorry for the late update....

Just finished testing voltage, while idling without aircon/stereo etc... we are at 14
with all lights/aircon/stereo turned on while idling it reads 12

I then went for a drive to investigate further

While driving without aircon reads 14
while driving with with aircon/stereo etc... it was still reading 14

It did drop down to 10 briefly when aircon was turned on but instantly went back to 14 and stayed there as i got as many electrics as i could running at the same time.

 

I would suggest it is alternator 90% likely as said by others.

 

In support of inpact blue, my car does the same thing - always has.