what can cause engine misfire?

tweety_5150 · April 19th, 2010, 03:05 AM

i have a 2000 gt it misfires not so often and the check engine light starts flashing i check the code and its cylinder 3 and 4 i already changed the spark plugs but it still keeps on happening any ideas?

JerseyTrueBlue · April 19th, 2010, 04:08 AM

Could be the coils, try checking them with a multimeter or something, if it's not them it might be an injector? There are a lot of things that could cause a misfire, start ruling things out by checking the obvious.

03SonicBoom · April 19th, 2010, 07:32 AM

There's only 3 BASIC things that will cause a missfire. Lack of fuel, compression, or spark. Start by figuring out which one you're missing and go from there. Like JerseyTrueBlue said, it's prolly coil pack or injector.

I would start by swapping the coil packs on cylinders 3 and 4 to other cylinders. When the CEL comes on again, see if the missfire has moved to the other cylinders.

RyanGT · April 19th, 2010, 11:29 AM

+1 move the cops to the other side, see if misfire follows. Then it is the cops.

tweety_5150 · April 19th, 2010, 11:41 AM

alright ill try and see if its the coil packs. how hard is it to changed them?

03_StangGuy · April 19th, 2010, 11:45 AM

I was getting my engine back together yesterday after a plug fouled out. Short story, I still dont know why but I noticed a weather tight seal for the injector on the cylinder isnt there. Not sure when I lost it but, its easy to make sure they are there. Cant hurt.

dcook_14 · April 19th, 2010, 11:49 AM

You take a bolt out of the top, take the old one out, put the new on in, re-bolt it, re-clip it. Should take about 30 seconds per coil

dcook_14 · April 19th, 2010, 11:50 AM

Originally Posted by 03_StangGuy

I was getting my engine back together yesterday after a plug fouled out. Short story, I still dont know why but I noticed a weather tight seal for the injector on the cylinder isnt there. Not sure when I lost it but, its easy to make sure they are there. Cant hurt.

Yeah those little o-rings pop off pretty easily. You can order new ones from Ford if you need to. I wouldn't use a regular o-ring since it's getting gas against the rubber... it'd probably eat regular ones after a while

tweety_5150 · April 19th, 2010, 12:42 PM

Originally Posted by dcook_14

You take a bolt out of the top, take the old one out, put the new on in, re-bolt it, re-clip it. Should take about 30 seconds per coil

wow i would of thought it would of been more hard ill give it a try later in the day.

April 19th, 2010, 03:05 AM	#1
tweety_5150 Enthusiast 2000 GT Convertible Join Date: Apr 2010 Location: Bay Area Cali Posts: 676 iTrader: 1 reviews	what can cause engine misfire? i have a 2000 gt it misfires not so often and the check engine light starts flashing i check the code and its cylinder 3 and 4 i already changed the spark plugs but it still keeps on happening any ideas?

April 19th, 2010, 04:08 AM	#2
JerseyTrueBlue Hardcore Enthusiast 2001 Mustang GT Join Date: Mar 2009 Location: New Jersey Posts: 1,857 iTrader: 3 reviews	Could be the coils, try checking them with a multimeter or something, if it's not them it might be an injector? There are a lot of things that could cause a misfire, start ruling things out by checking the obvious. __________________ True Blue Crew Member #2 315's Crew Member (Dat azz) 255/298 Founder of the please leave my signature alone, I want it to say what I put there and don't appreciate you deleting it club

April 19th, 2010, 07:32 AM	#3
03SonicBoom Moderator 2003 Grand Cherokee Join Date: Jul 2008 Location: Indiana Posts: 6,617 iTrader: 0 reviews	There's only 3 BASIC things that will cause a missfire. Lack of fuel, compression, or spark. Start by figuring out which one you're missing and go from there. Like JerseyTrueBlue said, it's prolly coil pack or injector. I would start by swapping the coil packs on cylinders 3 and 4 to other cylinders. When the CEL comes on again, see if the missfire has moved to the other cylinders. __________________

April 19th, 2010, 11:29 AM	#4
RyanGT MM Fanatic 2000 GT Join Date: Dec 2006 Location: Lynnwood, Washington Posts: 4,258 iTrader: 4 reviews	+1 move the cops to the other side, see if misfire follows. Then it is the cops. __________________ 2000 Black convertible GT: KB 15psi, and other goodies... 1971 Datsun 240 z: Header and rebuilt motor. (The DD)

April 19th, 2010, 11:45 AM	#6
03_StangGuy I Poop Entirely Way Too Much Blown 03 GT Join Date: Jun 2007 Location: Long Island NY Posts: 6,917 iTrader: 0 reviews	I was getting my engine back together yesterday after a plug fouled out. Short story, I still dont know why but I noticed a weather tight seal for the injector on the cylinder isnt there. Not sure when I lost it but, its easy to make sure they are there. Cant hurt. __________________

April 19th, 2010, 11:41 AM	#5
tweety_5150 Enthusiast 2000 GT Convertible Join Date: Apr 2010 Location: Bay Area Cali Posts: 676 iTrader: 1 reviews	alright ill try and see if its the coil packs. how hard is it to changed them?

April 19th, 2010, 11:49 AM	#7
dcook_14 Banned 2004 Mustang GT 12.35@114.08 w/ 1.88 60' Join Date: Feb 2009 Location: Waterloo, IA Posts: 7,015 Blog Entries: 2 iTrader: 7 reviews	You take a bolt out of the top, take the old one out, put the new on in, re-bolt it, re-clip it. Should take about 30 seconds per coil __________________ Do the Right Thing, Cook. ~Zip.

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