Intermittent/random Missfire...

[chromiehomie]

hi guys, bought a 97 a4 1.8t with the aeb engine, the guy said he thinks it was running on 3 cylinders, so driving it home and it seemed like it was hesitating when accelerating. it was however very intermittent so it would be smooth for a second then start hesitating etc. few more miles down the road onto the bypass and stuck my foot down and it turned into a violent jerking. I know the ICMs are a common fault on these but my ICM went on my old a3 and it didn't seem like it was running as rough as this. any ideas?

 

[aragorn]

Check for leaks around the inlet manifold.

 

[chromiehomie]

ill give it a check tomorrow, it seems ok when idling, not as often when its driving. Also when I took the engine cover off, I noticed a slight bit of oil on top of coil pack #1, im yet to take it out and see if there is any on the shaft or spark plug.

 

[aragorn]

My mums A4 was doing pretty much exactly what you described.

I replaced the whole ignition system trying to figure it out thinking it was ignition related.

Eventually i noticed one of the small hoses under the inlet manifold had split underneath so it was leaking on boost.

 

[chromiehomie]

ok cheers for that, i'll give the bay a good looking over and report back tomorrow