TD4: Slight increase in revs when idling

[Zejmjien]

I've tried search and found nothing. I've been noticing lately that when idling [at about 800rpm] the engine sometime increases revs by about 100rpm for a second and drops again. Any help please?

 

[Nodge68]

I've tried search and found nothing. I've been noticing lately that when idling [at about 800rpm] the engine sometime increases revs by about 100rpm for a second and drops again. Any help please?

Is the AC on?

 

[Zejmjien]

Haha noo at first that was what I thought was the culprit but a week after with ac turned on it returned

 

[Zejmjien]

Problem has not yet returned. too weird and erratic to work on