New to diesels, engine trouble. need advice.

[94power-stroke]

Hi,
I am totally new to diesel engines, and purchased a F250 back in September. It’s a 1994½ F250 4x4 XLT, it has the 5-speed manual tranny and of course the 7.3L Powerstroke. The truck has a 4 inch lift and 285’s on stock rims. I have put an aftermarket 3 inch downpipe in and have straight piped it. The truck is 247,000 miles young and now having completely rebuilt the front end, replacing the rusted out rear lift blocks and the other minor modifications (nothing electrical, or programmers). The last two fill ups I calculated 16.6 MPG and a 15 MPG, which seems low compared to other Powerstroke owners I have talked to. I have also recently noticed exhaust being puffed out from under the skirt of my dipstick, Blow by? vaccume issue?
The truck quit running right about a week ago. I have noticed the engine running a little more rough than usual and a loss in power. For example, normally I shift at about 1,500k RPMs and will putt around at about 1k RPM in town. At 1k rpm in 4th or 5th gear I could step on it and accelerate smoothly and quickly. Now at that rpm I get a vibration like I am lugging the engine but smoothes out around 15k-16k rpms . I currently have to shift at 2k rpms to get a smooth acceleration or I get that vibration.
Also, there is a long hill I have to drive daily to get home, but when I drive my truck the power difference driving up the hill has changed. I used to cruise up the hill at about 40mph@1,700 rpms and could put my foot into it and immediately hear my engine rev, hear my turbo, feel the boost and hit 50mph without thinking.
Now it acts like it’s gutless going up the hill. I have to drop a gear and go 40-45mph @ 2k rpms and if I put my foot into I get a slow methodical almost delayed acceleration. When It first did this I had to check I wasn’t driving a 3 cylinder geo metro (no offence).
Finally I noticed a clear yellow fluid drip a couple of times from my exhaust (I noticed it in the snow after idling). When I say yellow I mean like I had to check that my dog was still in the house and didn’t take a leak under my truck. Until I noticed a drop proceeding to bead up and drip once more. It was a very small amount of fluid, but it freaked me out.
For the most part the truck doesn’t smoke even when you put your foot into it, with the exception of a few minutes until it warms up on cold morning. It doesn’t leave oil on the drive way, or use antifreeze. The only thing I can say that actually doesn’t work is I can’t get my fuel gauge to register fuel in my front tank even though it will run off that tank. Rear one works fine.
Please help me figure out what’s wrong! One problem? Combination of problems?
Thanks,
94power-stroke

[c-j]

I would check the fuel filters first. Loss of power and ruff running are some symptoms.

[94power-stroke]

I just changed my fuel filter with a Racor filter shortly after purchasing the truck. I will double check my filter. thanks for the advice.