P0300 misfire, low EGR flow....idles rough

[jakefreese]

Well I parked the EX for about a month as I didnt have time to deal with the rear wheel bearings. I changed the wheel bearings only to find the battery was DEAD DEAD DEAD. No doors left open nothing plugged in. Typical crappy autozone batteries anyway.

Put new battery in and fire it up to go drive it. Kinda ran a bit rough after sitting a month, but was fine after about a minute. Drove it that afternoon no problems. Next morning jump in it, back to idling real rough now SES light is on. I had P0300 random misfire (no kidding) along with 2 other codes that Auto E didnt save. I thought it was EGR low flow. and P0100 diagnostics not complete.

Before I parked it, it ran perfectly. Any ideas? I have had thoughts of disconnecting the battery cables again and let the PCM totally die and see if it will wake up happy. During the freeze frame of P0300 it did show both of the #2 O2 sensors at 0 voltage. But I thought O2 Sensors would not cause a misfire or rough running unless they were really bad. Other than wheel bearings nothing else was changed.

Thanks for the help!

Jake

 

[apenland01]

Did you follow the PCM reset procedure when you put the new battery in? If not, it didn't properly re-learn it's idle values and whatnot. Reset the PCM following the correct procedure, then see if you get the same codes again. Misfire and EGR codes are different issues (like p0401 and p0300)

 

[Joe in NY]

there are many systems always running in a car that drain a battery

 

[jakefreese]

I didn't reset the PCM with the new battery. I did the PCM reset yesterday, now no DTC codes but the rough idle is still there. Seems like it's driving just fine, smooth power and normal power level. I did fill it full of gas with the worry that there might be some moisture in this junk ethanol gas.

I guess I'll keep looking through it.

Thanks!

 

[jakefreese]

Yep same problem even after PCM reset.

Getting

Random 0300
EGR flow insuffiecient 03
Mis #4 0304
Mis on startup.

I am going to PCM reset again, I think I will go ahead and put plugs in it since I actually got a specific cylinder misfire this time.

Any ideas on the EGR? Could there be something else mad that is causing that?

Thanks again!

 

[jakefreese]

I finally got around to it, I decided to throw an EGR valve at it since its the original one. My only thought is the EGR has been on its last leg and when the computer tried to relearn, it could not get it in the required parameters. It fixed the problem, I also put some new plugs in it.

It was happy as can be until it overheated this morning!