Video: low rpm at startup, P0081 error code

[cody888]

Video: low rpm at startup, engine code 81

hi.. so here is the problem with my car. it has low rpm at startup for 5 to 10 seconds. [YOUTUBE="engine low rpm problem"]SGg4mSGN4yE[/YOUTUBE]
but if I start the car with my foot on the gas, it starts with low rpm for half a sec and then its normal (I don't think this is good for engine)
engine error code is 81.
this happended after I reved the car to max for 2 sec to test the new exhaust (something I'll never do again with this engine!)
specs: 2000 civic auto,155k miles (about 250k km) on engine, no modifications.
also the oil hasen't been changed for about 15k miles (25k km) and the oil filter was clogged which I changed both the oil and oil filter but the problem didn't go away.

so what could be the problem? is it the o2 sensors? throttle sensors? should I change the oil again? or should I open the engine head cover and see if there is sludge or something there?
what can I do to diagnose the problem?

 

[lethal6]

The code is telling you where to start. That is what it is there for.

Also why in the hell are you waiting that long to change the oil? It's cheap and fast.

 

[RonJ]

Double check the code. The one you posted is not one that exists for your car.

 

[cody888]

Double check the code. The one you posted is not one that exists for your car.

good point. I was looking at generic code descriptions. the code is still 81.
this link shows code 81 is "central processing unti (CPU)", but does it mean ECU or ICU? because my ICU is almost fried. the intermittent wiper and some interior light dosen't work.. but I don't see how this is related to the engine.

 

[cody888]

I changed the ICU and reset the computer. no error codes so far. the engine low rpm seems to get less noticeable on every startup.