I guess the question is if any wd 40 spray vapour got to the cylinders. There should have been some effect. The no change is a reason to pull that exhaust manifold bolt unless you feel none of the wd40 made it. I hope it breaks free easily. You might want to try the wd 40 again through the air filter box first.

On second thought if the cylinders are being choked off pretty much by an exhaust restriction the suction to intake the wd 40 may almost be non existant. Normal airflow to and through the cylinders would almost be absent.

Also I now think the injection pump is probably okay. The lack of any response whatsoever to the wd 40. Plus this bog you mentioned on opening the linkage are good signs as far as my limited knowledge.

Do not get discouraged your problem will soon be located one step at a time. We have some members aboard that really know what they are doing. I have watched them help untold people and seldom fail to do so since I was allowed to join the site. You also communicate more than well enough to get through this.

For the time being I am ignoring your ohm readings for two reasons. I think without being absolutly sure that they relate to idle situations only. That circuit seems to be working if the idle rpms are as they were. Plus I still feel right or wrong that your car is not sophisticated enough electronically to create this difficulty.

Of course time may prove me wrong as I do not know it all. I only wish I had worked on an early 603 type engines a bit.

In theory only. If you opened up the linkage on the injection pump a bit. And either yourself or someone else were watching the tailpipe. The inability to burn the additional fuel efficiently Should be reflected by the exhaust getting blacker I think.

In a way the bog you get may just be the cylinders trying to extinguish with the additional fuel by reducing the amount of or efficiency of the burn. You have reduced the available oxygen even further.

I am also glad to see that you are cognizant of the issue of hurting yourself. Sometimes in the heat of frustration we all can do things that are not wise.