I come to you all in hopes we can pinpoint what is causing my CEL: P0301, P0303, P1399 which translates to cylinder 1, cylinder 3, random misfire codes.
Car: 2000 Honda Prelude SH
Mileage: 143,000 milesWhat has been done so far within past 5k miles:
NGK (6441-4PK) Iridium IX Spark Plugs
NGK (8019) HE65 Premium Spark Plug Wire Set
NGK 24286 Oxygen Sensor - NGK/NTK
NGK 24285 Oxygen Sensor - NGK/NTK
MagnaFlow 22644 Direct Fit Catalytic ConverterSymptoms:
The CEL came on, changed the cap and rotor because when I inspected the contact points looked a little burnt. CEL went away but after ~200 miles, the CEL came back on. I do not feel any misfires at idle or while driving. The car idles at 700 RPM and does not feel weak/bogging/sputtering when accelerating. One symptom I do experience is on a cold start, the car cranks about 2-4 times more before firing. Once warmed and starting the car, it fires right up without any sort of hesitation.
I went to autozone and bought a cheap set of NGK V-Power Copper plugs just to rule out faulty plugs and when I swapped them in, there was definitely bogging/sputtering during acceleration. I put the Iridium plugs back in and the sputtering went away as well as the CEL is gone however I have a feeling it will come back on within 200 miles. I managed to get a snapshot of the Iridium spark plugs when I switched them out with the V-Power, from top to bottom cylinder 1-4 respectively: Possibilities:
1. EGR valve and intake manifold ports clogged
2. Ignition Coil
3. Distributor Ignition Control Module
4. Fuel Injectors
My question is this:
Can a clogged EGR/Intake manifold port cause misfires? My father and a good friend who knows a thing or 2 about preludes thinks it's the distributor. Another friend of mine who works on preludes says that if I haven't cleaned the intake manifold ports and EGR, he would start there. What do you guys think? I'm pretty handy but before I start dumping a small fortune diagnosing this and tearing apart my car I would like to get some feedback. Thank you for any help!