Simple way to figure that out.
Put a timing light to it and rev the engine the timing should advance properly. If it doesn't there is an issue, however retarded timing is how we setup "antilag" tunes. It causes the exhaust gasses to be much hotter. I can retard the timing in a tune file and send that to you, I really doubt it will make any difference.
You could try removing the charge pipe from the throttle body, put one of those caps in the coupler with a fitting to attach a pressure gauge to. hook your boost gauge to it and see if you can create boost against a sealed environment. If it does not make significant pressure you have turbo issues.
Put a timing light to it and rev the engine the timing should advance properly. If it doesn't there is an issue, however retarded timing is how we setup "antilag" tunes. It causes the exhaust gasses to be much hotter. I can retard the timing in a tune file and send that to you, I really doubt it will make any difference.
You could try removing the charge pipe from the throttle body, put one of those caps in the coupler with a fitting to attach a pressure gauge to. hook your boost gauge to it and see if you can create boost against a sealed environment. If it does not make significant pressure you have turbo issues.