I have a 1987 190D 2.5 and it has developed a engine miss. It only misses at idle and up to around 1500 RPM'S. I replaced the o-rings and seals on the injector pump's delivery valves.
I think they torque at 10NM, what happens if one isn't torqued enough? Does the torque regulate the fuel pressure?

Please help....Rvroby@netzero.net

Torque does not determine fuel pressure. It sounds like you have a bad fuel injector. Now which one is bad? What I do is while the engine is idling, I loosen the nut holding line to injector and listen to see if idle rpm's change. If that injector is working, rpm's will drop. what you are doing is shutting off fuel to that particular cylinder. If engine rpm's do not drop, you found your bad one. You must do this for every cylinder. Keep rags handy because when you crack open that line/injector, fuel spurts out on engine. Do this quickly and carefully, and everything will be ok.