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I have been experiencing a cold start stumble just as the the temp gauge hits the first line since the weather got a little cooler. I was also getting quite a few misfires in cylinder 1 which I monitored via an obd app. This misfire triggered a fault code on one occasion.
so I decided to clean the inlet valves which was not as bad as expected. I found it harder removing the inlet than cleaning the valves. I used holts carb & egr cleaner and bottle brushes. I also had some small vacuum brush attachments to remove any bits left behind.
This had the effect of improving drivability, power and reduced the misfire counts but unfortunately I was still getting the cold engine stumble at the same temp range. I monitored fuel pressure only and noticed when not fully warmed up the pressure could occasionally drop. So £340 lighter I replaced the fuel pump which was a straight forward 45min job which I am glad to say has solved the issue.
i just thought I would share this experience as the fuel pump issues can not be obvious and only cause minor issues without fault codes. This could lead to lean conditions and engine failure. So don’t ignore these warmup issues as it could be the pump on its way out.
so I decided to clean the inlet valves which was not as bad as expected. I found it harder removing the inlet than cleaning the valves. I used holts carb & egr cleaner and bottle brushes. I also had some small vacuum brush attachments to remove any bits left behind.
This had the effect of improving drivability, power and reduced the misfire counts but unfortunately I was still getting the cold engine stumble at the same temp range. I monitored fuel pressure only and noticed when not fully warmed up the pressure could occasionally drop. So £340 lighter I replaced the fuel pump which was a straight forward 45min job which I am glad to say has solved the issue.
i just thought I would share this experience as the fuel pump issues can not be obvious and only cause minor issues without fault codes. This could lead to lean conditions and engine failure. So don’t ignore these warmup issues as it could be the pump on its way out.
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