Hey guys i'm trying to figure out whats wrong with this civic i have

Normally it idles at around 800-900rpm when warmed up, today i hoped in it and it started idling at 1500. I shut it off and started it back up and it dropped to 900. I backed it up into my driveway to clean it out.

When i left my house again it was back to idling at 1500, i tried restarting it and it wouldn't correct itself

Another issue is the torque converter refuses to lockup since this issue started ( its an automatic ), earlier that day everything was working fine.

Also the automatic gear position indicator doesn't really work right. Heres what i noticed

When the d4 light lite up without the headlights on everything worked right, the torque converter locked up and the car idled right. When the d4 light doesn't light up with the headlights off then the car acts all ******* retarded. When i turn the headlights on the d4 light ( and the rest of them for that matter ) will light up at their reduced brightness, if i turn the headlights off they just go out completely. Some times when the headlights are on the shift position lights on the gauge cluster will dim, I'm thinking maybe theirs an issue with the shift position switch in the console since if i smack the shifter the lights get brighter if they are dimmed.

ALSO ontop of all of this the car pumps out a **** ton of black smoke under WOT, and now since the idle is messed up it makes it under partial throttle as well. The car has a brand new denso o2 sensor

The engine is the stock d16a6 MPFI, i have no check engine lights. ( i had one for the o2 sensor which is why i replaced it )

 

the ECU controls the idle based on engine coolant temperature. I suspect what you are seeing is exactly that. if you driveit around and get the car to operating temp, the idle will go back below 1k.

 

The car was fully warmed up, it idles that high even if I drive it for 30 minutes on the highway

 

There is a fast idle thermal valve (aka FITV) that allows more air through the throttle body in the event the car is not warm, which helps control the idle. It may be stuck in the cold idle position. There are tutorials around here on how to remove it, clean it out, and adjust it. that is where I would go next, especially if you have no CELs, because it is mainly a mechanical device.

second, i have seen auto hondas do some crazy **** when the battery is not quite to full charge. Is your battery verifiably good and not super old?

It seems like you have a ground problem with the dash lights being crazy as well. I would rule those out as being a culprit before proceeding. the shift position device may very well be the culprit, but i would still investigate the battery situation first.

Note that none of these suggestions cost any money if you have some rudimentary test equipment, and some time to do some fitv cleaning.

 

stock d16a6 will not have a fitv. o/p i would check the wiring for your coolant temp sensor, the two wire one. make sure it isn't damanged, and also test the sensor, its under the distributor. hook it up to a multimeter and put it in some cool water in a pan on your stove, then turn your stove on so it starts to boil.

 

It did the same **** today while driving

I was driving with my cruise control set at 65 and everything was fine

All the sudden the cruise control kicked off and the torque converter unlocked

I popped it into neutral and I was then idling at 1500-2000 ( not bouncing )

I just drove it to where I was going and then shut it off.

I got back in it and everything was fine again for about 2 minutes then began being ******* retarded again

I then kept driving it to McDonald's

While waiting in the drive through I put it in park, it was idling high a **** as usual

After a few minutes it actually dropped on its own back down to the normal idle without me shutting off the car

I'm still in the drive through, I'm posting this while I wait.

I will check / replace those sensors when I get home. ( going to the junkyard so I might as well pull a few spare units