If the IP really is bad the car will stop running when it fails...... it shouldn't do any other damage if it fails. In that case you would just need to get a new IP or the old one rebuilt and have it installed. AT 121K the pump should be fine, not very likely to be worn out.

I don't know about this particular car but the lift pump could also be weak and not supplying enough fuel at high rpms, I would still think a clogged filter though.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k