Hi, I had a CEL come on and pulled the codes P1301 and P1399. I cleared the codes this morning and did some driving at lunch and after and it hasn't come back on, but I'm sure it will in the next few days. I'm pretty sure it's the cylinder one coil pack but the fellow I bought the car from is a dealer mechanic and he says he sees those codes sometimes that go away for good by just clearing them due to a bad batch of gas or something. He's an honest guy, so I think he'll help out if it's persistent, so I'm not too worried about it.

Anyway, one thing I am noticing is that the idle is different. It used to be that it would stick at 1 bar below 1K and now it alternates every 5-10 seconds between 1 bar below and 2 bars below. I've only had the car for a couple of weeks, but I've always had a habit of watching the idle on my Prelude at stops and have done it always with this car as well, so I'm pretty sure this is different. I was wondering if anyone else has an idle that is like this when they're warmed up.

I can't feel any shuddering and the car runs exactly like it did when I first got it. I wouldn't notice it if I weren't looking right at the tach, but I'm curious what a completely healthy s2k idle looks like. This is with everything turned off, in neutral, warmed up and stopped.

It's an 02 with 43K btw.

Any info is appreciated.

 

Start by swaping coil packs to another cylinder and see what code comes up next. Also try a "map whack". If you starting getting the codes on other cylinders it gets more serious.

 

Start with the "map whack". After that it gets a bit more serious... This is a common issue on the Ap1's it seems. Search for those codes here. We have discussed this before.

 

before resetting the code, retrieve the freeze frame data. that will tell you a lot.

since the misfire happened on cyl # 1, try swapping the coil pack to cyl #4, if the code follows the coil pack, replace it.

you might want to pick up a code scanner to rescan for pending codes. makes troubleshooting easier since it takes quite awhile before the CEL turns on.

i've personally replaced all my fuel injectors due to misfiring. of all the f20c injectors i've seen, they always come out pretty dirty (even if the car isn't misfiring). the ports in the throttle body will usually have lots of loose carbon bits.