[Engine] Intermittent noisy engine

[finianm]

1.9d 2001
At Idle speed the engine gets noisy (like old transit van). Problem comes and clears (could last for 5secs,10secs, 30secs )on its own. When i rev the engine the prolem clears but then could return at any time. Noticed that engine revs goes up from 900 to 950/1000 when problem is there. Happens whether engine is hot or cold. Changed egr valve and air flow sensor as these are known problems with engine. Also happens at low revs also when driving. Problem happens more in dry weather. anyone have any ideas?

Fin

[Sol]

sounds like injector sticking? the noise may be "nailing" caused by one cylinder getting lumpy fuel delivery or a bad spray pattern but its weird the revs rise.....could be some weird injector pump behaviour.

[finianm]

sounds like injector sticking? the noise may be "nailing" caused by one cylinder getting lumpy fuel delivery or a bad spray pattern but its weird the revs rise.....could be some weird injector pump behaviour.

Thanks Zion.
If injector sticking engine would be smoky. Feels as though timing is going out and the "tractor" takes over. I am going to disconnect EGR valve as they are known to be a problem part. Will let you know if it makes any difference.
Fin

[brodfather11]

sounds like injector sticking? the noise may be "nailing" caused by one cylinder getting lumpy fuel delivery or a bad spray pattern but its weird the revs rise.....could be some weird injector pump behaviour.

Thanks Zion.
If injector sticking engine would be smoky. Feels as though timing is going out and the "tractor" takes over. I am going to disconnect EGR valve as they are known to be a problem part. Will let you know if it makes any difference.
Fin

Air in the fuel system?