Rep Power: 0

Hi there,
I recently purchased a civic in poor condition (wish I hadn't now after $600 CA dmv fees uhg).
anyway it was running rough with high surging idle when I bought it. Now it SEEMS to run perfect, sounds like a sewing machine but still throws p1300 p1301 p1302 p1399 which seem to be cyl 1&2 misfire, and misc misfire codes best I can tell.
I first changed cap, rotor, plugs, wires and that basically made it run great. But still throws codes, so I swapped distributors with my 96 civic and still same codes, adjusted valves, no change, swapped injectors around to different cylinders no change.
i have not done a compression test yet, but it sounds very even when running and starting.
when I pull the plug wires one by one the engine rpm droos by about the same amount on each cylinder. It actually runs more evenly than a lot of other hondas I have worked on that had no codes, so I'm kinda stumped. Could this be a false reading? And if it was false how would I even go about stopping it from coding? If the MIL wont stay off i can't register it and I'll just have to junk it. After dmv fee's I have close to $1200 into this thing...and it's really an $800 car if I were to sell it 😅

One thought I had is a problem with the crank sensor... but I feel like that is pretty unlikely.

thanks for any useful suggestions!

 
Rep Power: 211

Start by doing an ECU reset.
1) turn off all interior electronics (radio, dome light, dash light, headlights, etc..)
2) disconnect negative battery terminal
3) discharge residual voltage by turning on headlights and pressing brake pedal a few times
4) wait five minutes and ensure all electronics are off
5) reconnect negative battery terminal
6) start engine and let idle for 15 minutes without engaging any electronics

Codes should disappear and hopefully will not return.
Inspect the PCV valve by shaking it (should rattle) and replace if need be.
Clean the IACV valve and gasket screen.

 
Rep Power: 367

97 is a 6th gen car - moved to correct section

 
Rep Power: 0

Thank you Hrpuffinblunts,
I did reset the ECU a few times already. I will inspect the pcv and air control valve

 
Rep Power: 211

If the cylinder misfire codes keep returning after ecu reset then it could be a failed crank or cam position sensor? Have you checked mechanical timing to rule out tooth jump?

 
Rep Power: 0

Yes I forgot to mention that I did already adjust the cam, when I adjusted the valves, it was off 1 tooth. I have not checked out the crank sensor, and I did have the thought that it could be throwing a false code, but I would think a flakey crank sensor would actually make it run poorly, but I don't know that much about exactly what the ecu does with all the sensors. Does it actually use cam sensor as well to monitor misfires? I thought it was only crank sensor.

The idle is also still on the high side. It has come down as I have worked on it, but still is in the 1050-1250rpm range in park, and that is with the throttle body idle screw all the way closed. (Idle stop screw also set correctly)

 
Rep Power: 0

Well thanks for trying, but I decided it wasn't worth the time to troubleshoot anymore. Got $280 from salvaga yard. I put all the old parts back on before junking it and the MIL light stayed off all the way to the junk yard 😅 Frigging cars! Who who knows what the deal was, oh well 🙄

 
Rep Power: 211

May have been bent valves?. Anyway, it's a parts car now.

 
Rep Power: 0

Maybe very very slightly bent. I pulled out the new plugs that I had just put in and the cylinders that were coding were a little brown whereas the other two where white and looked almost new.

I def made the right choice junking it though, just before pulling in to the yard the brakes went to the floor and then came back suddenly. Then again in the yard they asked me to park it and just backing up slowly the braked failed again and I almost drove over a human and down an embakment! Very scary. I threw it in P and pumped the brakes then at the last second they came back 100% again. (Shoulda gone for the E brake, but didn't think to in the moment)