"Fueled out" and losing power at high speeds? (617t)

[RobTheMod]

My 300SD likes to use a bit of oil (1 qt per 1000 but it leaks quite a bit of that) but fires off with very little glow, can reach 100+ on the flat, and only loses steam on really big hills (such as the one outside Indio, CA eastbound on I-10- "Shut off A/C next 10 miles" read the signs)... it just has a very disconcerting tendency to lose *all* its forward momentum at 70+, you slowly lose speed until you're doing 50.

This is on level ground. Speaking of the Mojave, that's where it happened Sat AM while heading to L.A.... very scary, you panic, is it gonna die entirely? When this happens, a few interesting notes: I have a Dawes boost controller set to 13 psi and a VDO gauge. Boost at speed varies 5-13 psi depending on pedal position. I can usually, at 70, have 7 psi on the gauge, stab the pedal, and get anything up to 13 depending on how hard I "shuffle" on the pedal. When this happens, the boost drops to 5, stays there even with the pedal on the floor, and here's the "fueled out" part- no smoke. Nothing billows out behind.

This makes me think it's out of fuel, can't flow any more, can't make any boost to speak of. Letting it coast down to about 40-45, then flooring it usually brings back full whoooosh back up to whatever cruise I want.

Tank strainer? I had something similar to this- the car wouldn't exceed 67 mph and didn't smoke at all, max boost 6 psi. New filters fixed that. This new power drop is disconcerting in the desert, and only happens every few weeks.

[Scott98]

Sounds like you already know what to do first. New fuel filters, clean the tank screen, blow out your metal fuel lines.

Good luck,

Scott