Strange lurching. Need help.

[ventureforth]

So, a little while back, my Rabbit started lurching at low-rpm when giving just a bit of throttle.  It is an '82 1.6 NA.  Did some searching and found some people with similar experience after a gov mod.  Problem is, I don't have a mod.  Here's what I can tell you:

1. The lurching is such that if I'm only slightly depressing the throttle, in any gear, it bucks like a bronco.  If I go WOT, the lurching stops.  If I take my foot off the throttle, the lurching continues a bit, lessening as it goes, until it's back to normal and comes to a stop.  Happens in 1st, 2nd, and 3rd, for sure.
2. I have done no mods to my motor.  It has relatively new OEM Bosch injectors and nozzles, a new clutch, and all hoses lines seem to be in good order.
3. It is burning oil for sure (if that has anything to do with it).  I lose a quart or more in-between re-fuels.  There's a slight bit of seepage, I think, but oil loss is definitely from burning.
4. The only thing I have done to the motor is turn in the fuel screw a little bit.  Doesn't overheat ever.  Runs brilliantly on the freeway and at 35mph+ around town.
5. Starts up every time like a champ.  Only smoke is at WOT and it's black (or dark dark grey)
6. Replaced a transmission mount.  There's a bit of a rattle on cold start, but it goes away quick (like a few seconds of running or as soon as I engage a gear).  Basically, if I put it in gear and move even a foot, and then back to neutral and idle, the rattle/shake is gone.
7. Lurching happens both as I accelerate, or when I try to cruise at low speed.  For instance, pulling away from a stop, if I'm just casually accelerating, it reaches a point in the power curve where it lurches once (a big one) and then we're smooth as I get over that point in the rpm range.  Or, if I'm in slow traffic on the freeway, just trying to cruise along at around at a low but appropriate speed for a given gear, it buck like crazy until I either accelerate or let off.

What else can I tell you?  What other info might help identify the issue?  Is it mount related?  Is the burning oil (which I need to fix -- bad o-rings?) a sign of some greater internal problem that would cause this?  I tried turning the fuel down, but it didn't really help.  It's idling a little fast, but not so bad.  I think I turned the idle up a bit to get rid of a little bit of the shake.

Thoughts?

Thanks.

[rabbitman]

Will it do it if you push the go pedal slightly in neutral?

I kinda think its got something to do with the gov springs........one might have broke but it seems unlikely, rather it could be bound up.

If you have a parts IP you could swap the whole gov spring assembly, it isn't too hard and is probably the most likely culprit.

[fatmobile]

Check all IP mounting bolts.
 Including the ones holding the bracket to the block.

[Fredrikkk]

I have the exact the problem with my turbodiesel. Mine lurches like crazy when I depress the pedal a little bit. It goes away if I give a little more gas, but it is annoying... 

Hope someone can contribute with something smart!

[bajacalal]

I know this isn't really much of a solution but have you tried one of the diesel fuel system cleaners like Diesel Purge or Power Service?

It seemed to work for me, so I would think something is binding up internally due to some sludge crap in there.

And no transmission fluid, motor oil, unprocessed bio, etc., in your diesel, right? 2 stroke oil is ok I think.

[ventureforth]

So today I was driving around with the cold start pulled all the way out, and the lurching wasn't so bad.  Still experienced it a little in 1st gear, but it was virtually non-existent in all other gears.  I even tried to make it happen, and couldn't.  I could feel it start to want to do the lurching thing... but it never actually got there.

So...why is that and does it provide a hint as to how to fix it permanently or what the actual problem is?

Thanks.

[ventureforth]

Would it indicate that the timing is retarded a bit?  And curious how that could happen, if so, since from one day to the next nothing was changed on the vehicle.  Or is it just wear and tear and the bolts get loose and the pump moves on its own due to engine vibration?

[rabbitman]

How many rpm does it get to when the lurching stops? I wonder if the advance piston is in there moving back and forth and pulling the cold start steadies it.

[Powjetta]

I have the same symptoms with my pump but I don't drive it much now.  My pump is still factory stock.  I finally chalked it up to wear in the pump.  If you come up with a solution be sure and let us know.

[stewardc]

I'm watching this intently. My 15000km rebuilt (modified) pump and 1.9 superdiesel does this with great regularity and it's extremely frustrating. I've tried absoluteluy everything, but it still continues at some level. Enriching the fuel screw helped a little bit, and additive also helped a bit, but it's still there.

[R.O.R-2.0]

I'm watching this intently. My 15000km rebuilt (modified) pump and 1.9 superdiesel does this with great regularity and it's extremely frustrating. I've tried absoluteluy everything, but it still continues at some level. Enriching the fuel screw helped a little bit, and additive also helped a bit, but it's still there.

my car used to do this till i put a new throttle cable on it..

my cars, the culprits have been worn out motor mounts, and crappy throttle cables..

[stewardc]

I'm watching this intently. My 15000km rebuilt (modified) pump and 1.9 superdiesel does this with great regularity and it's extremely frustrating. I've tried absoluteluy everything, but it still continues at some level. Enriching the fuel screw helped a little bit, and additive also helped a bit, but it's still there.

my car used to do this till i put a new throttle cable on it..

my cars, the culprits have been worn out motor mounts, and crappy throttle cables..

Both new here.

[R.O.R-2.0]

I'm watching this intently. My 15000km rebuilt (modified) pump and 1.9 superdiesel does this with great regularity and it's extremely frustrating. I've tried absoluteluy everything, but it still continues at some level. Enriching the fuel screw helped a little bit, and additive also helped a bit, but it's still there.

my car used to do this till i put a new throttle cable on it..

my cars, the culprits have been worn out motor mounts, and crappy throttle cables..

very veird...
Both new here.