Howdy guys. So I have been trying to diagnose this problem for a few years now with no luck. I'm out of ideas. Here's the back story. 06 jetta tdi with a salvaged title. It was in a pretty serious front end collision before I bought it and was put back together as cheaply and shitedly as possible. Within 500 miles of me driving it off the lot the JB Weld and bubble gum started breaking loose. So the current issue is this: Starting off in first gear I need to hit the accelerator and get it up to about 2000 rpm's before I begin to let out the clutch. If I don't and just let the clutch out (car idles at 800 rpm) while giving it gas it will act as if the engine is lugging, then almost like it is flooded. If I keep trying to accelerate the engine will begin knocking. It will slowly build up enough speed and rpm's to get past this and then let out a glorious black cloud of smoke. Again if I goose it up to 2000 rpm's before letting out the clutch it is fine most of the time. This will also happen in second gear if the rpm's drop below 2000 rpm's. FIXES attempted: I did have a check engine light on for awhile since this has been an issue. Glow plug #4 and a MAF sensor. I cleaned out the MAF sensor and replaced the broken glow plug harness and the check engine light is now gone. The problem is still there. Another interesting fact is that the problem is even worse the warmer the weather is. Any help would be greatly appreciated.