Now that I'm on E85 I am getting occasional P0300 Random Misfire Detected. I don't feel anything. Does not seem predictable at all. I never had this on gasoline.
New plugs gapped tight at 0.020".

Any ideas? Is this simply coincidence?

 

"The Check Engine Light is a DSM badge of honor. It means that your car is fast!"

Mike W of RRE

 

What kind of timing are you running at cruise and idle?

 

I had the same thing happen when I first switched to e85. It ended up being a lean condition at idle. I could be rolling up to a stop and have it pop up. I run my Idle rpm neutral and idle rpm drive no less than 1K. I think it's a little more common with cams and bigger injectors if your timing is to low. I run no less than 11* at idle. I have the RC1000's and 272 cams they don't like stock timing.
If your trims are spot on try some timing and do some logging.

 

Bryan, at cruz I'm at 38* and at idle it's 15*. Idle is set at 991rpm.

 

You may have hit on the cause. I had the idle at 1,000 and just recently set it back to OEM. I've now put it back at 1,000.

 

Do you have a freeze frame of when the CEL was triggered?

 

Not exactly sure what you mean? Do you mean a data log?

 

yeah he means a log of the instant the code was set off, so you can see what all was going on at that exact point in time..

 

OBD2 stores information on what was going on the instant the CEL was triggered.

If you use scantech you can see this information.

 

LMFAO!!!!! oh man thats awesome!

 

I've received P0300 codes previously and seemed to happen in low RPM or idle situations. It dissapeared recently, didn't do anything different with the tune.

 

Mine is getting worse...

I'm getting the dreaded P0300 everyday, sometimes 2-3 times per day. I would not really mind except that whenever I have a "code" the CEL blink-on-knock functionality is DOA.

 

Just thought of something...

I'm turning off closed loop by setting the load switches to all zeros. Is that a bad idea? Could that cause or exacerbate a lean-at-idle condition, especially at drop-back-to-idle situations?

Maybe I'll try going back to closed loop for idle, but retain open loop for cruz? I doubt I'm actually wasting much fuel at idle anyway.

Comments welcome...

 

Try pullung back some timing at idle, Thats way higher then what I am running..Also what rom version are you running?