Hey all,

The gf was driving on the highway and noticed the check engine light on. Not sure if it came on at startup or on route. She had it scanned at a garage and they said it is a po300 MISFIRE. They said it is ok to drive the rest of the way to where she was going (40 minutes highway)...

What does this error mean and what might have caused it?

thanks!

 

P0300 Random/Multiple Cylinder Misfire Detected



This could be bad fuel or water in the fuel.


This a general code, until something more specific appear I would add a container of fuel line antifreeze (it's alcohol) in case it's water and refuel at a different place for a while. But that's me

 

Hey there,

Well, I did fuel up and then drove 2 hours highway with no check engine light. It just happened this morning when she used it....If it was the fuel, I would assume that would have come on when I was driving it for the 200km yesterday right?

Also, the rubber seal on the lip of my hood has become unglued and probably isn't seating properly to keep all the water etc out of the engine bay. Could something have gotten corroded or wet that might cause that error to be thrown?

It is safe to drive with this code correct?

 

so they said it was most likely due to putting the truck in gear before the rpms dropped in the morning....The service dept said Mitsus are very sensitive to that.

BS??? Not sure, but the GF could have done that.

They reset the code and it hasn't come back on....

 

So would misifiring cause this issue:

when accelerating from a stop, it gets to third gear I think, the revs drop due to the shift into third, but then the revs stay there for a second then drop a bit (maybe 250-500rpm), then climb back up...And during this I have not eased off on the gas. It isn't hard acceleration, just normal.

thoughts? The dealer reset the code, so the CEL hasn't come back on, but I found myself thinking the car wasn't driving normal a few days before the light actually came on (seemed to be harder shifts and when automatically downshifting, it would upshift as quick if I accelerated again.

Any advice or thoughts would be great.
Thanks!

 

Hi all,

I got a "Service engine soon" first thing in the morning, had Autozone guy run an OBD scanner, and came up with P0300 code. I did put 3/4 tank of gas in just yesterday so this thread caught my attention right away. I am in Boston and we had ~15 degree weather all day yesterday. Questions for you pros:
- I have an 2007 Outlander XLS and I added approx ~10 gallon of gas (which I assume is bad). If I go with Heet gas antifreeze, how much should I add, 1/2 of the bottle?
- Should I reset "Service engine" light and then see if P0300 comes back
- I don't have an OBD scanner so I need to get one to do a reset. Is it OK to get a cheap one (~$30) or more expensive ones worth the money? I do basic maintenance myself (oil change, tire rotation) and take it to the local mechanic for anything more serious.
- Should I just take it to dealer (45 min away and I would have to wait for it there). I am the second owner. I think 5 years/60k miles warranty still applies but not 100% certain.

Thanks is advance

 

Same code as op. Misfire random. Are you for sure knowing that its the bad gas that you put into your tank thats casuing this. Yes, cheap OBD2 scanners still works, they jsut read codes and clear them, nothing more lol. Whats the mileage on the car? Have you replace plugs, fuel system service and such? If you know is the fuel for sure, clear the light and just put in a good tank of fuel and drive it for a while. See if the light ever come back on.

 

ShortyRider: Mileage is 36k (we don't drive much). Have not done anything with the plugs/fuel system. No engine/drive train problems in the past four years.

Don't know 100% but "water in the gas" seams to fits my symptoms:
- Filled up (3/4 of the tank, 87 octane, Hess gas station next to the high-way) yesterday and drove home right away
- Local temperature all weekend was around 15 degrees and snowing
- Started up the car this morning (park in the garage) and got P0300 code right away

I figure I start with OBD scanner and clearing the MIL before doing anything expensive/invasive.

 

I have seen this on my 2011 Lancer 2.0 with 5 speed manual since new. Now is 27K and got P0300 again three days ago. I just read it using an OBD2 code reader. I do not clear the code. Just wait and usually clears itself in about 2 days.

When the engine is cold the rpms just go up and down a lot sometimes upto 2500-3000 and I do not like this. Supposely this is normal... they programmed the computer to do that to warm up the engine faster (a warmer engine pollutes less).

Personally I do not like that and try to drive away after 20 seconds. Sometimes when I backup from my parking spot the engine shakes like its cold and the "engine" light comes up. I read the code and its P0300. I ignore it since goes away on a couple of days.

I do not think is good idea to rev up a cold engine especially since I live in Canada and the temperature is around -20 °C. I believe this could wear the engine. I prefer to drive at low rpms for a few blocks and allow the drive train to warm up instead of idling at high rpms. But the fully synthetic oil and 10 year warranty helps me try to ignore this. Anyway If I could reprogram the computer not to idle so high when cold, I would.

 

My 2009 also threw a code about 2 weeks ago. Had a friend hook up an ODBII reader and we got P0000 - which my basic google search decoded to mean "Everything is good - carry on".

Cleared the code, hasn't come back yet. Put winter tires on the day before so I can't tell if my fuel mileage is worse because of those or the code.