about every 10k miles i have to adjust the throttle linkage because the RPM gets so low that at a stop light it will almost cut off if i do not shift into neutral this has been going on for nearly 100k miles now and i am almost out of adjustment could adjusting the throttle linkage just be a band-aid or do i need to give the old diesel a tune up the injectors or glow plugs have never been changed we change oil and filters regularly at 5k intervals