First post so sorry about format.
I have a 91 Accord with some idle and power issues, when idling the rpms waver between 100 and 1700, and when going to drive if you press the gas the rpms drop to between 100 and 300 leaving you near dead in the water, but if you can get it up over 2400 the car works normally, As in were talking no power issues revs fine and you can drive smooth, but only after that 2.4k point. I’ve replaced the fuel filter (which hadn’t been done in a while, the fuel in it came out looking like chocolate milk) checked the code it was throwing and replaced the #1 o2 sensor, and all the spark plugs. I’m planning on dropping and draining the tank to clean it but I’m wondering if anyone else has any other ideas.

 

If you had bad fuel in the system, you could have a damaged or clogged injector. You cause also have a clogged fuel pump pickup screen or a clog in one of the lines. The idle problem could also be because of this but you should know that Hondas are known to have idle issues and that it is usually because of the IAC system or "Idle Air Control". This system uses the engine computer to monitor engine rpm and operate an electronic solenoid air valve. Since the main throttle valve or butterfly valve is closed at idle, the engine doesn't get air that way, instead it gets bypassed in by means of the IACV or "Idle Air Control Valve". The valve can become contaminated with dirt and oil and the electronic solenoid itself can also become damaged internally causing it to not operate correctly. This is sometimes accompanied by a check engine light and a ecu fault code but not always. Other things that can cause a wavering idle are the FITV or "Fast Idle Thermo Valve" as well as air being trapped in the cooling system.