Help please with Code po300 that popped up.
I was driving home today & upon making the left onto hwy ramp the car starts to hesitate & starts to loose power. It made it up to hwy speed & I continued driving thinking it may have been some water sucked into the CAI. (I drove this morning in tropical storm conditions with a very powerful hard rain coming down. Lots of street flooding.) I see the engine check light flashing & my AFR is a steady 10. If I hit the gas it would jump up to 12.5 & back to 10. So I know its rich & I 'm thinking a short in the wire harness that runs the fuel injector bank on one side. ( had the wire chafe issue about 7 months ago & fixed that). I get home & run the code display & see po300 H C, car smells like sulfur (Cat plugged?) I plug in the ODB II scanner (The Android phone version) but its not showing a code? I shut off the motor & restart it & it runs just fine. The code display now shows PO300 H. What do you guys & gals think. Water sucked in & code set ?, Plugged cat that cleared? No fuse blown so I'm not thinking another wire short. If it was a broken valve spring it wouldn't fix itself??
Okay I just checked wires and looks well. I removed my Donaldson air filter & found this (see pic) I think a chunk of rubber may have got sucked into intake (small chance?) but car is running fine now? I need a need filter element. ZO6 size (about 4 inch opening) Hallteck said that filter is no longer available. I will need a replacement,any suggestions?
Photo of filter.

 

Crankshaft position sensor

 

Why would you say that? That's the little sucker behind the starter motor. Need to remove header to get to it. PIA for sure. Wouldn't that throw a code?

 

I would say that because thats the definition of the code. Yes it is on the back of the crank.

 

Okay thanks I'll look into that if it reoccures.

 

a po300 is random misfire. Could be many causes for that. Hopefully something just got moist and it won't be back.

 

You have to read the code(s) with something other than the DIC when it's happening.

 

Yes I thought I would be able to retrieve it with my Android code scanner app. It worked well twice for me in the past but this time it didn't even pick up the code. I should have plugged it in when it was running & the code was H C. Once the code goes into history the app doesn't see it. I have had no issues with the car since the incident. I put about 80 miles on it with multiple start cycles. Hope it was a blip on the radar.
BTW I got a new Hall tech Venom intake coming it included the honeycomb air diffuser. Maybe a little better performance or a couple of horses from the stinger I had?

 

Last time I got a P0300 it was a loose plug wire on the coil.

 

I have had this same code pop up twice this past weekend. But it only seems to miss between 1500-2000 rpm. That's right at freeway cruising rpm. I can feel it miss and stutter, and it gets worse if I stay in that rpm range, above or below it seems to dimminish. My guess for possibilities is.

1. Plugs
2. Wires
3. Coil packs
4. Crank position sensor

Any other ideas??

 

Are you getting a CEL or P0300 when it happens?

 

Cel? Just got the code one time than back into history on the restart.

 

CEL = Check Engine Light.

Scott

 

I get a flashing CEL and when I check the DIC it reads a P0300 C

 

The DIC will NOT show specific cylinders misfiring (p0301-p0308)

 

Yes I did get the CEL.

 

You need to check when it happens before key off.

 

Update: No codes & drove about 200 miles since incident. I would have to guess it was either one of a few things
1. Water intrusion into engine setting off misfire.
2. Crank sensor starting to go bad.
3. Air filter tore open on turn & creating disturbance in air
flow to MAF setting off code with possible rubber debris/water into intake..
I did get a new Halltech C5 Venom II filter kit. Man that thing is twice the size of the original Halltech stinger that had the Donaldson element. I do need to relocate the MAf to right in front of the TB & I'm looking for a 02-04 Z06 MAF to accommodate the large opening for the bellow. I guess I'll need a tune for the MAF change also.
Anyone have a 02-04 Z06 Maf for sale. I would like an OEM unit.

 

You have to be careful about driving through deep puddles. My secondary AIR system got all kinds of screwed up after a freak, major downpour dumped on me while driving in Dallas (over 1 inch in less than 10 minutes). It caused all kinds of vacuum issues and cost me a trip (and a nice chunk of change) to have the system tuned out so I could pass inspection.