HELP! Changed oil now engine misfiring!

I have 2 other related threads to my oil change saga, but this seems to merit a new thread.

My Jeep: '94 XJ SE 2dr 5spd 4.0L

All I did was change my oil and now the engine runs very rough. It used to run as smooth as a dream and now I guess it is misfiring. If I rev it in neutral, it seems ok at higher RPMs, but driving around town it sounds and feels horrible. It is still a bit rough when I gas it in neutral though idle is ok.

The differences - I went from old, black conventional 10W-30 to Quaker State full synthetic 10W-30 plus one quart STP oil treatment.

It does seem to start a bit easier.

I was only able to run the engine for 10 minutes before draining it, so it may not have got hot enough. It sat for a 30 minutes or more and was still dripping out. So after I loaded up 6 quarts and ate lunch, the dipstick reads past the safe line, maybe 1/4 to 1/2 of a quart.

STP is really sticky. I have never used the stuff before but it is slow as snot. Any chance it's stuck to some of my valve rockers on the top where I put the oil in. When I run the engine really hard it seems to stop misfiring but of course I have dummy lights and no tach.

Am I running too much oil and need to pull the filter to let some out?

Should I drive it hard and hot for a while to get the STP snot where it belongs?

Do I need to reset the ECU?

This has to be the dumbest problem ever.

I don't see how an oil change could cause a misfire. I'd check to see if you bumped a crappy connector of some kind of sensor or broke a vacuum line.

That's what I'm thinking. But I don't think I touched anything. Had to unplug the sensor by the oil filter and plugged it back in. Unless there is something near there I hit. There is so much room to work I doubt I broke anything but I will take a second look.

Maybe I didn't plug the sensor back in fully? That's the oil temp sensor right? I will go double check now.

Ok I am dumb and fixed it, sorry to wast everyone's time.

I pulled off the oil temp sensor and one of the two holes on the connector was fully clogged with grit so I cleaned it.

Then, Oh look! One cable on the distributor is completely off! A couple more are loose.

Feel free to delete this thread or leave it up as a warning to other's idiocy.

why did you unplug all that stuff to change your oil?

rockclimber said:

why did you unplug all that stuff to change your oil?

Click to expand...

Right?!

The oil temp sensor is always in the way so I am used to that routine. I have big hands and probably pulled it when I was threading the filter out by the distributor cap, with gloves on.

Welcome to the forum! We should start a "why the f@&# did I do that"

Here's mine: I was so excited when I got my Fumato oil drain valve. So excited yhat I forgot to close it: 5 quarts of Rotella on the ground. I saw it rinning out from under the jeep, or it would have been 6:explosion

I was trying to take off a really obnoxious oil filter my son (the gorilla) had tightened on there and apparently partially pulled a couple of spark plug cables loose. Started the motor up, it ran like crap, so I decided to shake a few plug cables to try and figure out which ones were the issue. I sure wish I hadn't done that with my crotch tight up against the fender.:wow:

As long as it wasn't a 911 moment, all is good.

8Mud said:

I decided to shake a few plug cables to try and figure out which ones were the issue. I sure wish I hadn't done that with my crotch tight up against the fender.:wow:

Click to expand...

So was it a nice snapping blue spark...youch....shocking!!:idea:

ParadiseXJ said:

So was it a nice snapping blue spark...youch....shocking!!:idea:

Click to expand...

Kind of gives a whole new slant to the term "bone headed".

It happens. At least it was an easy fix.