M30 misfires while cruising but not while accel. (Anymore)

[The München Monster]

So i've had this issue for a while. M30 would misfire pretty bad while driving, found out the first lead wasnt even working. Ok. So replaced that and now it accelerates amazingly, smooth as hell and i have some power back. But still got minor tugging and missing at certain RPMs while cruising at a constant speed. I intend on replacing all the other leads, because even though they do work and there is a connection they are putting out a lot of power and they seem a bit loose on the plugs (Yes i've made sure they are on there, they just dont seem to fasten very well). Any ideas as to how I could misfire while cruising but not speeding up? I've also found oil on my plug closest to the firewall, replaced it but not sure if its like that again. Dist. and rotor are supposedly in good condition

[csermonet47]

Make sure everything is grounded properly. Sounds like an issue I was having then I found the main engine ground was loose. Tightened it up and everything was good to go.

[Bearmw]

I would also do a good visual inspection of all ignition parts including all plugs, wires, cap, rotor, coil, and relays. Also inpsect the connectors, wires themselves, and grounds as was already mentioned. Once I was satisfied with how things look I would check resistance levels for the CTS, CPS, and the wires to the ecu itself. A harness this old may have some internal wire corrosion, and/or breaks. It may be time consuming to do all this but being methodical and checking everything is the only way to really figure things out.

Beyond that make sure you have a Bentley manual, get the ETM for your engine, and learn to use a logic probe.

Good luck.