Any suggestions on power loss?

[jbach36]

A few years ago, I had a REAL problem going up the mountains of VA/ W. VA. I was going up at 40 mph, with trucks coming up behind me at 70 mph.

We originally thought it was bad fuel, but that wasn't it. I later found out there's a THIRD fuel filter, the strainer in the fuel tank. That was clogged with algae, we cleaned it, and that fixed the problem pretty well.

I'm now having a bit of a problem climbing hills again so I thought the sludge on the fuel tank strainer was back. I had the entire fuel tank taken out to be cleaned, but .....the fuel filter wasn't clogged. The other 2 fuel filters are new.

The only clue I have this time is that the car stutters a bit on the first start up of the day, then after a few seconds it runs normally. If I get to a big hill, it starts losing speed. I wonder if there could be an injector that's messed up? I had them cleaned last year but they were not pop tested.

1991 300d, 205k