Starts out smooth, then what the buck? Options

[Jesco Reient]

When I first start the car cold for the day. (2056, D-jet, Raby 9590 cam, timing 27 advance @3500) The car has no cold start valve but has not seemed to care. First start it runs smoothly pulls away from the house shifting @ 3500 it acts nicely. After warming up for awhile as the motor reaches 3200 to 3600 it bucks severely then above 3600 it smooths out a bit. Then as it gets warmer the bucking moves down the RPM range to 2600 to 2800 RPM becoming not very drivable. any ideas out there? (IMG:style_emoticons/default/confused24.gif)

[boxsterfan]

http://members.rennlist.com/pbanders/DJetP...tm#troubleshoot

I assume you have been going through the info in this website. It was very helpful me to me when I started out (and still learning D-Jet).

One thing listed here that is relevant to you is:

What:
Engine "bucks" or jerks at steady part-load throttle settings

Check these:
Throttle switch contacts worn
Dirty, worn, or misaligned trigger contacts


Fix with:
Replace throttle switch. See throttle switch section above for more detail. If condition
persists after testing the throttle switch, it may be due to defective or misaligned trigger contact points.


Maybe you could borrow a known good TPS from someone?