Here's the background. I've been so pumped about my new changes I added them to my sig days ago. This last go round, heres what got changed:
BTS tranny, regulated returns, FASS, stealth pump.

I have two issues to ask about. One is perceptual, one I'm pretty certain is going to be a return trip. And in all fairness, I have all kinds of faith in the guy who did the work. But we changed a lot of things, and you know. This stuff happens.

So, issue #1 is I am hearing something very different which sounds, at least, like exhaust. I can hear every puff from the engine. I didnt hear it like that at all before. Previous to this work, the up pipes did leak, which makes it harder for me now to determine what "normal" is. But it sounds like the tail pipe is right next to the firewall. And I dont see, or feel, for that matter, anything blatantly obvious when I open the hood.

#2 is the lurching. I drove it quite a bit this afternoon. Something just felt awkward. I perceived it driving at all speeds, I couldnt put my finger on it until I was on the highway and slowing down. I hit right at 47 mph and you could feel the truck just jerking, like a bad engine miss. If I went 50 or 40, it almost went away. But if I held it right there at 47, that seemed to be the sweet spot and it would darn near rearrange your spine. And that one I know is wrong but I'm at a loss for.

The only thing that I can think of, which I dont even put a lot of stock in, is the fuel. The FASS was a replacement for the stock system because it had gotten so gunked up. I would think the fuel filter would still catch any garbage in the lines that got through the screens before it damaged an injector, but ? ? I dunno.

I'm lousy at diagnosing so hoping for some educated SWAGs.

 

My 01 has exactly the same lurching or chugging problem at the same speeds very annoying and could never get to the bottom of it either.

 

It might be useful to know what things you've done that are non stock. Correlations, you know. I have a couple of theories but I dont know if either is worth a spit.

 

I think I have the same problem but I notice it more in 3rd gear with TC locked and at a steady food on pedel. I think its trying to blow off some boost yet gain boost at the same time, almost like it doesn't know what to do so it flutters. I am new and learning about these trucks so if that sounds stuped let me know.

 

how many miles do you guys have on the oil? is it old or fresh? these trucks don't fare to well with bad oil in them.

 

Fresh mobil delvac 1 for me my truck has done this since new

 

For me, this just started. I'm keeping my ears pricked a lot this weekend, and the oil was just changed.
I almost started to wonder today if the sound I'm hearing really is an exhaust sound. The regulated returns are new, I'm trying to correlate foot on pedal, rpms, and sound . . . it struck me that I could be hearing fuel pumping. Thats a complete stab in the dark though. I'd like to see what someone else with all the same stuff has going on.