Ok My wgon, 1990 GLE 16Valve DOHC engine, the 234f was running rough.
so after seeking advice on the Brickboard(thank you all) I have :
replaced the plugs , the wires, cap and rotor, pulled out the injectors and replaced all the seals, tested the injectors, nice even spray pattern.. taken out the flame trap and cleaned it out, checked for vacuum leaks,
the operation has improved a bit.. I found that #1 and2 plug wires were reversed and it still ran somehow. finally I asked my son if he had tested the compression.. he did but could not remember the numbers.. so I pulled the plugs and.... 150_0_150_150..looks to me like a bad piston ring or valve. so I dumped some oil in the cylinder and no change. BTW the plugs were all good except
#2 which was fouled. .So then I pulled off the valve cover to inspect the cams and valves.. cams and valves look good from what I can see, at least the springs did not look broken.
so, what it appears is that I have to pull the head and find out which valve is bad and replace it. I assume I will go to the local NAPA machine shop.
when it cranked It appeared that all the valves where going up and down the full stroke, at least we could not tell any difference without measuring equipment. my assumption is that the valve or valve seat is bad and needs replaced.
I am amazed at this car, it has plenty of power and runs hard with 3 cylinders, just runs rough and vibrates.. well not so much after I put the wires in the right order..heh.finding another b234 motor or head has not been possible yet. any advice? what should I look for?
almost forgot.. the exhaust manifold gasket is broken at #1 and needs replacement, which will happen as soon as it arrives in the mail.

all advice is appreciated.
Tim W