940 No turbo

Previous post on this matter is now several pages back, so I am posting here for further comments.

My meaning for hesitation as required some bricksters for further evaluation is this:

Car would not pick up in speed, and in fact rpm would come down, while stepping on the gas pedal. If I try to floor the pedal, I could distinctly hear some popping sound, probably backfiring, at the front (engine) compartment. I guess from this description, I could rule out the auto transmission as suggested by the AUDI mechanic.

I changed the fuel pressure regulator and notice some improvement, meaning the hesitation is not frequent and happens more often when climbing slope and when engine has just started to run(hot or cold).

Another observation is that when I pull the vacuum hose from the fpr I could see some gummy substance inside, which I cleared with a long needle. It is breathing okay now but does not seem to be the cause for the hesitation. I opened the throttle and notice the same sticky brownish substance on the wall of the throttle, but is blocking up the holes. What are those, and is this a symptom for something more serious?

Also when I turn the throttle drum (where the kickdown cable is attached), the kickdown cable does not spring back to be taut and remained loose. Only on repeated turning of the throttle drum it sprang back to taut position. Is this normal or has this to do with the hesitation.

Appreciate all your comments and help, and would like you all to continue to help with my predicament.

Thanks as always
Laozong