what are the most likely cause for misfire

**scotthd** · 05-06-2008, 09:11 PM

My car has had the ses light on for some time code 1440 evap emiisions system I changed the gas cap and reset it came back so i ordered a purge solonoid. but the other day my ses started flashing indicating missfire and the code I think was 0300 for misfires... My question is could these be related or should I dig in more..I only have 54,000 on it.

**Orcus79** · 05-06-2008, 09:39 PM

Miss fire can be caused by many things, anything from a clogged filter some where to a bad sensor. Get a for sure code and that may help diagnose the issue. The 0300 code is multiple missfires I think.

**scotthd** · 05-06-2008, 09:47 PM

that was the description so that must have been the code but do you htink it has anyhing to do with purge solonoid

**Orcus79** · 05-06-2008, 09:51 PM

I dunno, it could be. So far I haven't had to diagnose it on my car (02 WS6), and the most likely culpret you don't have, the EGR.

**scotthd** · 05-06-2008, 10:01 PM

thanks for the info.

**danziger** · 05-06-2008, 11:38 PM

The only time I had a mis-fire code, it turned out to be a faulty spark-plug wire. Sounds obvious, but it happens to a lot of people...

**SteveC** · 05-07-2008, 05:25 AM

Get it fixed soon, the P0300 will trigger the P1336 code, and then you will need a crank postion relearn.

SteveC

**GatorSS** · 05-07-2008, 07:13 AM

Most of the time, P0300 code is caused by:
1) spark plug(s)
2) spark plug wire(s)

Before replacing these, check to make sure it's not just a loose plug wire.

**scotthd** · 05-07-2008, 03:41 PM

thats what I figured I changed the evap solonoid today code started flashing again So I ordered new msd wires and ngk 55 plugs... I hope this fixes it Im also putting cat back on this weekend if it arrives soon enough I havent driven since it occured and it first came on down the street from my house... I dont know if this indicates something dif but I can smell alot of fuel in the exhaust right now also

**Orcus79** · 05-07-2008, 03:49 PM

you are running rich, so, something isn't metering right, or plugs are not firing, how is performance?

**scotthd** · 05-07-2008, 04:39 PM

dont know I parked it when the ses flashed...

**Cutlass** · 05-07-2008, 05:59 PM

Yep usually plugs and plugs wire fix the P0300. Can also be dirty/plugged fuel injectors or bad gasoline.
P1440 doesn't exist. You either mean P0440 which is EVAP system large leak. That usually sets when you leave the gas cap off or a EVAP hose disconnected.
Or you have P1441 which is vacuum during a non-purge condition. The purge valve is almost always the cause there.

**scotthd** · 05-07-2008, 08:06 PM

you are right it was a 0440 evap emiss control system malfunction,,I cleared both codes after replacing the solonoid.ran it again this time 305 came up cylinder 5 misfire. runs pretty rough still strong gas smell, I hope plugs and wires do the trick, not looking forward to changing them the passenger side looks pretty tough....

**sic2001** · 05-14-2008, 08:07 PM

My car threw this code today so was wondering what the solution for yours was. Ive been having a problem of when I tip into the throttle in a low gear my engine detonates and pings. It runs great every other time except "tip in". Plugs are new, wires are a year old..