Rough running on a 1.9

flyturner

Newbie
Joined
Jul 20, 2020
Messages
4
Any thoughts appreciated. Recently serviced with vacuum lines replaced. Now started hiccuping and jerking after 3k revs upwards Been doing this for around 4 weeks. Let fuel run down and topped up but no effect - thought it might have been supermarket fuel issues.
Cheers
Paul
 

NZ00Z3

Zorg Guru (III)
Supporter
New Zealand Zeds
Joined
Dec 9, 2014
Messages
988
Location
Timaru, New Zealand
Model of Z
3.0L, 2.0L Z3 Roadsters
Do you have a scanner? Can you download the trouble codes and post the code number and descriptions here? It would also be good to see the short term and long term fuel trims. Both at hot idle and after 30 seconds at 3,000 rpm.

The first thing you think of with rough running is vacuum leaks. You have replaced the vacuum lines and the problem is getting worse above 3,000 rpm. This is the opposite to what a vacuum leak does. They are worse at idle and go away at rev's.

How old are the spark plugs?

Is there any oil in the spark plug wells shorting the plugs to earth? Caused by old valve cover gaskets.

Have you replaced the HT leads to the plugs?

Could it be the expensive coil pack failing?
 
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