1998 OX66 runs rough @ low rpm

[TwoWisemen]

Hi all-

I have a 1998 OX66 that runs very rough from idle to 1700 rpm. I put new plugs in after I cleaned the O2 sensor. I feel like one cylinder is not firing. The motor is new to me and ran great the first trip. 5800 rpm @ WOT the first trip, now 5100. Engine does not want to stay between 1700 and 3200 rpm. It will jump up to 3200 as I accelerate and falls to 1700 as I decelerate.

I know that this motor doesn't always run on all 6 cylinders, but I do not know when and which ones stop firing. If someone can tell me that, I might be able to determine if a cylinder is not firing when it should. Sorry for the long post, thanks for any help.

[jb123]

run motor in driveway at about 1000 rpm and pull each plug wire at at time and listen for the rpm drop/sound change to isolate a non firing cllinder.you can do the same with each injector.

if you ave an o2 sensor it should be checked along with the vapor tank interior filter.

[TwoWisemen]

Per other posts, I checked VST screen and that wasn't it.

Are all 6 cylinders firing at 1000rpm? Where can I find which cylinders drop at which rpms? Or does the non-firing cylinder vary?

Will a faulty O2 sensor make the motor shake so violently that the cowling looks like it's going to come off at just above idle? I think (hope) that cleaning and inspecting the O2 sensor removed that from the possible causes list.

Thanks for any and all input...

[formula29]

engine must be at or above 1200 rpm for all cylinders to fire,