JD 250 fuel issue

[mayor]

I have a 2000 JD 250 with 1000 hrs on it . It started to flutter this summer after I bought fuel that was delivered to the job so I ran some lucas through it and changed the filter and now plowing snow with it it is getting worse and losing power under a load could it be the pump on top of the tank or something in the tank or injectors . If some one knows more it would be great help. thanks

 

[skidsteer.ca]

Here is a link to the manual
http://www.mediafire.com/?l22595v2mp03t

 

[skidsteer.ca]

duplicate