Bucking with initial acceleration, D-Jet Options

[Montreal914]

I've been trying to solve an issue that makes the driving rather unpleasant (IMG:style_emoticons/default/headbang.gif)

I have a 2056 D-Jet that I daily drive. Recently I replaced the fuel filter and since then, the car has developed this behavior which I don't see why it would be related. When I put in first gear and get going, the car doesn't pick up and is bucking. As I progressively press on the pedal, it suddenly picks up and gets going normally. While it's trying to get going, I've noticed that my A/F gauge tends to go lean and out of range.

Things that came to my mind: faulty throttle switch which influences the fuel delivery, hence lean.

On the TPS, I checked the open/close circuit of the 2 traces with the 10 switches and everything is good. Idle switch kicks in also. I checked the resistance of the whole D-Jet harness on the 25 pin connector at the CPU as suggested by Anders and everything is within range.

Replaced the points and adjusted Dwell. Fuel pressure is set at 29psi (analog gauge inline).

I swapped the TPS, the CPU, the MPS, the coil without any improvement.

I'm running out of ideas... (IMG:style_emoticons/default/sad.gif)

Maybe someone has experienced something like this (IMG:style_emoticons/default/confused24.gif)

[914_teener]

I had a very similar problem a while back. Cutting out and bucking at low RPM's

I turned out to be the CHT ground. McMark...Mark now Mid Western transplant made a custom CHT ( not sure where he got the thermister) with a separate ground. I installed it and it has been performing well since, about a year or two ago.

My theory is that due to heat cycling and the metals involved it eventually builds up resistance at the ground contact on the head and starts causing problems.

Testing in situ means checking the resistance to a known ground with your trusty DVM and then is tests out fine.

I suggest removing and replacing or cleaning it as some others have suggested and then see what happens.