For a while now I have been having an issue with loss of power & shuddering while driving and car reving at ~1200 RPM for good solid 2-3 minutes when I start it first thing in the morning. as near as I can determine problem is much worse in summertime than in winter. I have to let the car settle and drop down to normal RPM range before I put it in gear. if I put it in gear right away, it will shudder for couple of minutes or worse even stall. so far I have changed DIC, sparks, all of 4mm vac lines and throttle body.
I am strongly suspecting that this is not one problem but combination of problems that is causing this behaviour.
* changing throttle body made shuddering much more tolerable
* changing DIC made loss of power less noticeable
* changing vac lines hasn't had much of noticeable impact
* changed Turbo bypass valve yesterday and that made loss of power and shuddering completly disappear except for shuddering that still happens at first start of the day ( but it's only been a day so far ).
What else could I look at? is it likely that my fuel pump has become weak and takes longer to prime now and is due for replacement?
Also after I changed TBV, I noticed that old TBV had it's diaphram wet with oil. is that normal or am I looking at yet another problem?