Well I'll describe this as best as I can. One day I changed my oil. I put a little too much in so I drained it and refilled. Now after that it started a misfire thing where it would stutter between 2-3K and kind of bubble at an idle. It didn't do it all the time. Maybe 1 in 7 times I drove the car. So I got frustrated and took off my intake manifold, throttle body, fuel rail, and injectors to clean the sensors and check everything out. Idiot me, I broke the banjo bolt on the fuel rail. So I ordered a SS fuel line from Fast-Turbo.com ( ) Now I put everything back together, started it up. Same thing happening at idle but now when I hold down the gas is surges. It'll go up 1-200 RPM's and drop. If I hold the gas to 4k it'll cut back down to 1400 while I'm still holding. I reset the ECU. Checked the CEL and got 10, 12, 14 which is the same ones I had before I took it apart. If anyone understands any of this let me know what's going on! I know you Prelude Guru's can figure it out. Thanks,

Ryan

(I think I'm going to drastically reduce my asking price in my sig...lol)

 

Idle surge is usually always caused by one of the following; FITV needing adjustment, IACV needing cleaned...or a vacuum leak anywhere from a bad hose to a bad seal between throttle body and intake manifold. I used carb cleaner to find my vacuum leak, just sprayed in bursts around known trouble areas until the idle changed just a bit...letting me know where I sprayed sucked in the carb cleaner and needed to be fixed. It was the seal between my throttle body and intake manifold.

As for the car running rough/sputtering/misfiring...it's either fuel or spark. Start cheap and check your spark, clean your plugs, make sure there's no oil or water down in the sparkplug tubes, etc. Check fuel pressure, check connections, etc. If nothing is found...might be your distributor coil starting to die. I had a similar problem on my 91 Integra...then one day it wouldn't start anymore. Distributor coil was shot.

Post a reply after checking all that stuff, and let us know.

 

if you insist on doing this yourself, buy a helms manual and follow the troubleshooting guides for the IACV, IAT and EGR.

 

I have a PDF version of a 1993 Prelude Service manual, I think that's the same thing. Do you know what page it's on? It's over 1000 pages!

 

its in the idle control and PGMFI sections. Both are right next to each other.

 

I have a 92 si that has the same problem after i changed the coolant intake pipe...i have seen that i have to bleed the coolant to stop it from bogging out just wondering if thats true or not

 

sounds like you have some vacuum leaks, causing those codes. idling surging up and down is the FITV. I Believed thats the one, it uses the coolant to regulate your rpms when you first start your car. had the same issue 9 months ago. Take it apart and clean it thoroughly. this is a symptom of bad coolant system also. your ECT senors are probably gonna go bad soon if not already. DTC 12 is EGR, remove and clean super good. use a vacuum pump to check it before and after your cleaning installation. I have the 93 service manual also. follow the steps and you should be good. Good luck

 

Ok before i changed my coolant intake pipe it worked fine...it was just leaking real bad and started to over heat very fast...im not that smart when it comes to cars put me on a computer and i can do magic since thats my field, anyway i have learned alot from this site and will like to continue on learning from the honda pros up here... what is a FITV and is it easy to clean