I have a 1997 integra gsr and its was throwing the cod p0505 occasionally and was idling kinda rough and surging and then today cel started blinking. i pulled these codes

P0301- Cylinder 1 misfiring
P0303- cylinder 3 misfiring
P0300- random / multiple misfire detected.
P1399- Manufactures control Ignition system OR Misfire
P0505- IAC or IACS idle air control system

and went and bought plugs and nothin. From what i have read i heard all these codes minus the iac could be lots of things(injectors,dizzy,plug wires, head gasket,) but i need to narrow it down where should i start? none of the other threads have the iac code with it???? my plugs looked white when pulled also

 

do some testing and good old fashioned diagnosis before you load up the parts-shotgun and fire.

white or tan-ish is optimal. with no deposits (plug color). if you have deposits like ash, it can indicate oil burning. (since you changed plugs and still have missfire, i wouldn't put the problems source here, however)

are all plugs equally colored? or are cylinder 1 and 3 worse than 2 and 4?

if you have a D.V.O.M (digi voltage meter) pull the harness off the dizzy and test resistance to assure you're in spec. if you only have the problem when warmed up, it could be the coil or wires (heat raises electrical resistance, causing some problems not to show up until up to certain temps)

test your spark plug wires' resistance

get yourself a spark tester and test each plug wire one at a time to see if you have adequate voltage to each plug.

how long has it been since you changed your fuel filter? does the car break up at high rpm? this could be an indicator of insufficient fuel flow.

it could also just be a bad iacv. insufficient airflow at idle causing a missfire.

you can also attempt a tried and true seafoaming.

 

My guess is lean misfire. I had similar codes except the P0505. It was a combination of a bad headgasket and a leaking injector.

 

well a leaking injector will cause a rich missfire.

 

Ok im having the same problem exactly the same codes.......except on long trips like hr or so drive my RPM start to Jump so im cursing around 80mph at 4000rpms then it lags out drops 500 to 1000 rpms so between 3000 and 4000..after a long drive i louse spark only happen one time.......my modes in the car i got it with all this stuff..its a 96 GSR 2door..Mode Skunk 2 intake manifold..DC headers..AEM V2 intake..full exhaust..
i think the DIZZY is bad cuz i did throw a ICM for a min 2.....any advice i didnt change my fuel filter im about to check out what you recommended up there plese let me know if any of you know......i got the car and they did maintained it i change

spark plugs. spark plug wires..cap and roder (did have the no spark problem till i did cap and roder)
i dont think they new to run premium too for the poor maintainace..but i do run Chevron but mostly Shell. VPower... well get to me thank you

 

i had misfire codes and did everything..

One thing i gotta ask.. does it sound a little more different? is it getting BAD gas mileage?.. Burnt Valves!

 

Check your timing to ensure the timing belt TDC position is correct, if it off by a tooth or two it will give you the 300 type CELS you refer to along with misfires.