replaced all the coils and still check engine light

[chocolat1701]

i got a ls 2001 v8 with 200k miles, i pulled the codes and i had 4 bad coils so i decided to replace all 8 coils and get a all new spark plugs, so after we replaced all the coils i still had a issue with coil 3, we replaced the coil and spark plugs with coil number 2 and still had same issue with coil number 3, so the issue is not the new coil or spark plug, the only thing i can think of is possibly the fuel injector needs to be replaced. any ideas. also when i got the car the check engine light never comes up the bulb may have been removed by the previus owner so i need to know what type of bulb the LS uses so i can replace i went to autozone and they dont have on file the bulb. does any one know? any help will be apprecieted.

 

[drag214]

Are you getting a code for a missfire in cylinder 3? The problem may be the spark plug. It may not be properly gapped. Don't go swappin parts. It can get expensive. Did you notice alot of black fluid in the spark plugs wells and on the ignition coils? If so, you'll need to replace your valve cover gaskets. The black stuff is not oil, it's fuel. The fuel is shot into the cylinder but because of the bad gasket. It leaks past the oring and fill the spark plug well with that half burned fuel sut. When the ignition is sent through the coil, It shorts out throught the fuel, on to the block. That causes the missfire, bad ingnition coils, and if it is not corrected, the raw fuel will burn the catilist from you catilitic converters. ( You will smell rotten eggs from your exhaust.)

 

[chocolat1701]

yes im getting a code for it, now we replaced the coil and spark plug from cylinder 3 with cylinder 2 and the problem didnt carry over so i dont think its the spark plug or the coil now the mechanic that changed out the coils didnt notice any oil in the cylinder or anything unusual about the cylinder, now if it was spacing on the spark plug then the problem would of carried over to the other cylinder. especially since i replaced all 8 coils and spark plugs with the same brand. what do you think?

 

[chocolat1701]

the actual code is p0303

 

[chocolat1701]

the mechanic that installed the coils and sparkplugs could not fix the issue he said that its a possible foulty fuel injector. and the other possibility is a vacuum leak or fuel presure. when i first did the job it had 6 codes now im done to 1 so im doing progress lol.

 

[SlickLS]

the actual code is p0303

I had the same code when I put my car back together after the timing assembly replacement. My problem was a fuel injector not plugged all the way on in. Start the car then go around a press to make sure all the connectors are tight.

 

[Quik LS]

as an FYI - the misfire by cylinder is a 'best guess' situation. there is not a knock sensor in each cylinder - so the PCM has to guess a little about which cylinder should be firing and if the misfire is related to it - so it can often be wrong. Most of us swap all coils and plugs since the labor is the big part of the job.

 

[chocolat1701]

thank you all i will try to remove the plug off the fuel injector and then plug it back in to see if that works, if it dont i will replace the actual fuel injector.

 

[kingofmy_h]

How do you know which number is cylinder 3,7,8 etc? I have a misfire on 7 and do not know where 7 is.

 

[cammerfe]

front
5 1
6 2
7 3
8 4
KS

 

[Madmaxpr]

Fuel Injector

+1 on the Fuel Injector.

Had the same problem last year, replaced it and all troubles were gone!

 

[chocolat1701]

ok im going to replace the fuel injector this week also i do hear the beep of the check engine light when i turn the car on the mechanic says that the check engine light is turning on but the CEL may be removed or just taped off, does any one know how to replace or remove the dash so i can do this myself all the mechanics that i go to are charging me $110 or more to just change a light bulb. does any one have any input?