Okay here goes, headlights on day or night and using power steering or ac will make the idle bounce between 1000 - 1400 rpms. So headlights on and extra load applied ON then OFF will bounce my idle. Help guys its been bugging me for months now. it only does this when the headlights are on...so idk whats going on.

 

Run some extra ground wires from the battery to the body, extra ground from the alternator to the body, if this does not help then get your alternator load tested at a alternator shop.

 

i tried it and nothing, I'm thinking it to be the TPS. When I start my car fully warmed up it will idle fine and stay at 750 rpms, but then if i give it gas to like 1800 rpms it will then drop to like 900 go slowly to like 1100 then very very slowly go back to about 950 rpms. It doesn't smoothly go back to normal idle. Pretty much go down, up a bit, then stay at 950 rpms which is like having high idle causing it to bounce. I tried disconnecting the tps and it stayed at 1100, but if i gave it some gas it would smoothly return back to 1100. So is it a faulty tps? Any advice would be appreciated.

 

It is not the TPS, you have to understand the theory of Honda idle, its quite long and I have posted it before,sorry you have to get out your searching skills this time. The idle goes up, the computer sees the TPS is at rest, so the computer thinks the car is decellerating and cuts off the fuel injectors. Due to a vacuum leak or another bad sensor (many) the computer turns fuel back on and up goes the idle again, this process will continue until the true issue is fixed, of course, tracking doen the issue is at hand. It is possible that too much AC voltage coming out of the alternator due to a bad diode skewing the computer causing your idle issue, but there are a half a dozen issues that cause a fluxuating idle, not usually the TPS.

 

Well do you know why my idle returns so slow and why it doesn't go back to normal. When I start it warmed up its 800 rpms, but driving it around for awhile it will drop to only 950 no lower. Why does it do that, and why does it return so slow???

 

i had the same exact problem, word for word, and just figured it out a few months back. somehow my idle adjustment screw backed out and was letting in too much air, and the iacv compensated. play with it and see what happens, but remember where it was in case its gotta go back