misfire code

[cndand72]

replaced all plugs , wires & coilpak , cleared codes & 2 months later engine light back on & same codes ( misfire cylinder 1) anybody got an idea what else to do to fix??????

[walker12]

you got the 3.4L? pull the plug and look for dark lines in the white porcelain.
3.4 have problems with carbon track

[jd-autotech]

could be the fuel injector, try a flush

[Tech II]

Wonder if he ever got it fixed?

Doubt carbon tracking on new plugs and wires.....

Did he use A/C Delco plugs? Good wires? Good Coil?

Basically, you use a spark tester and check output at the end of #1 and #4 wires....if ok, and used a good plug(OEM), could be the injector......another possibility is a head gasket leak, usually at #1 cylinder....is he losing coolant or overheating?

[cndand72]

Originally Posted by jd-autotech

could be the fuel injector, try a flush

I haven't tried to flush it but I have used several injector cleaners

[cndand72]

Originally Posted by Tech II

Wonder if he ever got it fixed?

Doubt carbon tracking on new plugs and wires.....

Did he use A/C Delco plugs? Good wires? Good Coil?

Basically, you use a spark tester and check output at the end of #1 and #4 wires....if ok, and used a good plug(OEM), could be the injector......another possibility is a head gasket leak, usually at #1 cylinder....is he losing coolant or overheating?

Plugs & wires are good , only overheated once filled coolant & not a problem with that since. Other than change oil light keeps coming on when it was changed in May shouldn't need to change it already.

[cndand72]

Originally Posted by cndand72

replaced all plugs , wires & coilpak , cleared codes & 2 months later engine light back on & same codes ( misfire cylinder 1) anybody got an idea what else to do to fix??????

Replaced the control module too & still same code.

[Tech II]

Is it a specific code, like P0301 or P0304, or just random misfire like P0300?

Fact it overheated, and all you did was add coolant, means you did not fix the coolant loss problem.....

How did you determine it was cylinder #1? Did the plug in #1 show any signs on it of a problem?

Adding injector cleaner to gas tanks, does not fix injector problems...that is just for maintenance....but before we start blaming injectors, lets check other things first....the only way to check an injector is with a resistance check, a coil check, and a flow check.....these require special tools only a garage has....

I would get the vehicle warm......then pressure test the coolant system overnight....next day disable fuel and spark.....remove #1 spark plug, and have someone crank it over, and look to see if any coolant comes out of the hole.....

You saw no external leaks? Check under the throttle body, on top of the engine depressions of the block.....if lower intake is leaking, you will see coolant "pooled" there....on opposite side it will be under the P/S pump....also check the corner of the head(passenger side) of #1 cylinder for a leak...

Need spark, compression, and fuel in a cylinder.....if you have good spark, using a spark tester at the end of #1 and #4 wires, if you used good plugs(OEM), if compression is ok, and no coolant comes out, then we might have to look in the direction of an injector....