Unsure about recent problems. I recently filled up at a truck stop, cheap diesel. Afterwards, I noticed performance problems. Motor feels out of tune, weird vibrations. Erratic idle, motor dies. The car loses power when driving up hill, slows down to 10 MPH. Also, my transmission seems to hesitate when freeway driving, won't shift into passing gear. I'm wondering if this is due to fuel starvation. Could this be injector related, clogged fuel filters? Is an injector cleaner available? Could fuel issued affect transmission performance? Vacuum issues perhaps? Thanks for any input.

Probably poor quality fuel.

Poor fuel = poor power = poor shifting.

Change your fuel filters and run fresh fuel from a mini tank under the hood, bypassing your fuel tank.
Performance should return.

If it does, you have a bad batch of fuel.
You may be able use the poor fuel by treating it with a regular diesel or a cetane booster.
You may need to use a biocide if you keep clogging filters.

Always carry spare filters and the tools to change them.
Only buy from high volume stations and never buy when the underground tanks are being filled.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022