Hi guys...here's one for ya. I am really stumped on this one. I don't understand hondas at all...I have a 93 Honda Accord with a fluctuating rpm issue on closed throttle (why I say closed throttle and not just idle is cuz it does this while driving too, if I leave the car in gear and let the rpms drop below 2000rpm is starts fluctuating making it wicked annoying to drive...I have to keep the rpms above 2000 to drive the car so it wouldn't jerk every time the rpm jumps). Not on a cold start but only when the car is warmed up. I did a lot of research for fluctuating idle issues and followed all recommendations including adjusting as well as replacing certain parts and bleeding the cooling system and nothing has helped at all...Here is what it does: I start the car in the morning, it idles a bit rough but it idles at a steady 2100 approximately and then after 2 minutes when the rpm is supposed to start dropping it begins to bounce around instead between 1000-2000 rpm...It is bugging the heck out of me. I replaced the IAC, FITV, the Japanese annoyance valve (dunno what its called, the one on the side of the intake that supports the FITV), the throttle body, the collective of sensors/valves that are in the box fed by the three vacuum hoses from the throttle body, charcoal canister, spark plugs, all coolant sensors, thermostat, egr valve, distributor cap, and rotor. I checked compression and have 180psi across all 4 cylinders. Bled the cooling system multiple times. Disconnected O2 sensor to see if it made a difference and it didn't make any difference at all (dunno if it should). I could really use all the help I can get. I dumped a lot of money into this car and I was hoping it would last me through college. Thanks in advance.

 

possible vacuum leak in the intake somewhere. check all vacuum lines make sure no cracks and they are all connected and no open vacuum ports.

 

Ya, you obviously have some sort of vacuum leak. You should get some carb cleaner and spray around the intake while the car is idles until you find the leak. You will know because the idle will change when you hit the suspect area. I'm assuming the iacv and fitv were new. If not, they could be bad if you got them from the junkyard.

 

Like they said above clean and check every vacuum line, there are not too many for an Accord. Go further and check the egr solenoid and the egr plate under the fuel injectors. What kind of motor does your accord have?

 

https://honda-tech.com/forums/honda-accord-1990-2002-2/95-accord-ex-idles-high-revs-when-put-park-3092687/

Scroll down a little bit, there is a detailed guide on checking the vacuum lines.

 

Alright. I found the problem. The spot where I replaced the fuel injector has a blown out intake manifold gasket. I can see right through it. Thanks for all the help guys! This was something I should have checked right off the bat before replacing all this stuff, lol.