Is it normal for the engine to sound as if it is cycling...speeding up a little and then droping back to normal?

are you sitting at idle at a light when this happens? or are you talking about when she's actually in gear and moving.

my idle speed varies when sitting at a light. the IACV might need cleaning.

Is it normal for the engine to sound as if it is cycling...speeding up a little and then droping back to normal?


In today's cars there are a number of variables that will cause that condition. Voltage regulator, Air conditioning, cooling fan's, just to give you an Idea.

Mine seems to do it when it's cold. After it warms up, It does not have that tendency. However, my Wife's E does it from time to time. I notice that it will coincide with a momentary dimming of the headlights. Mine's an 06, the wifes is an 05.

It would help if you could describe the conditions that are in play when it occurs.

Dom

Sounds like you might have a bad ELD. Mine kinda had idle problems before I changed mine out.

Yeah I'm with Dom. My 04 will do that when the cooling fans or A/C fires up. It's just a short burst from the engine and my lights will also dim. I'm pretty sure it's normal.