I've completed my second Pork Barrel as I used the cheap BBD's last time and always wondered how could it get better sounding then this? So I build this one with the 3007/3101 and I just tested it and I've got bypass then clicked on LED lights up and sounds just like bypass. Adjusting the trim pot changes nothing. I did substitute 2n4401's for all the transistors as I'm out of 5088's but this wouldn't cause that issue would it? And D4 is just left entirely alone and not jumpered right? I'm going to begin checking voltages and such now just thought I'd get a head start on the transistor and diode question.
There are a number of threads about Pork Barrel problems. I had the same symptoms as you, and it turned out to be a bad 3101. See this
http://www.madbeanpedals.com/forum/index.php?topic=13805.0 (http://www.madbeanpedals.com/forum/index.php?topic=13805.0)
Hope it helps
Got any pics? Also, are you sure your diodes are oriented correctly?
Post voltages and did you check the transistor datasheets to compare pin-outs?
Yes D4 is not jumpered. I put the diode in my MN3007 one by mistake and it would distort slightly. I just cut it off and no more distortion.
D4 is entirely empty, I'm waiting on a new 3101 first to rule that out or not. Seams not only like the easiest place to start, but likely as I'm not to fond of the source I got it from the first time. Small bears 3101 should be arriving monday or tuesday. I'll chime back then.