Code: Cylinder 4 Missfire

[GreeleyGal]

Getting the code that cylinder 4 is misfiring, here is what I have done so far to trouble shoot. Plug wire 4 from coil is showing spark, the new spark plug also shows spark but it is black from carbon but no oil. Switched injector 4 with 2 and still received error on cylinder 4. Code reader also brings up icon for catalyst monitor and oxygen sensor monitor. Could the cat or O2 sensors somehow affect the firing of cylinder 4? I would think it would affect all the cylinders. Could the coil still be bad even though the wire had spark?

Help would be appreciated, thanks!

[xxxJohnBoyxxx]

Originally Posted by GreeleyGal

Getting the code that cylinder 4 is misfiring, here is what I have done so far to trouble shoot. Plug wire 4 from coil is showing spark, the new spark plug also shows spark but it is black from carbon but no oil. Switched injector 4 with 2 and still received error on cylinder 4. Code reader also brings up icon for catalyst monitor and oxygen sensor monitor. Could the cat or O2 sensors somehow affect the firing of cylinder 4? I would think it would affect all the cylinders. Could the coil still be bad even though the wire had spark?

Help would be appreciated, thanks!

How is the spark. At night is it a nice blue spark? or a weak orange/yellow spark?

It needs to be a strong blue spark. Maybe install a new wire and plug and if it doesn't go away I would think you have a bad coil.

I say this because you already did a good job checking the injectors. Only other check on the injector would be good positive to #4 at all times. When key is on to fire the injector when the DME calls for it you need good 12+ volts at all times to the injector.

John Smith

[GreeleyGal]

The spark from both the wire and plug were bright blue. I am thinking of taking things back apart including the manifold cover and making sure the gaskets and such are in the right place. There is a definite vacuum leak and I am guessing it is on the back side by that cylinder. At this point it is a process of elimination so any more ideas would be appreciated.

[tiFreak]

if you have good spark and it's still misfiring it's a fuel delivery problem, you might have a plugged injector

[GreeleyGal]

Originally Posted by GreeleyGal

Switched injector 4 with 2 and still received error on cylinder 4.

Help would be appreciated, thanks!

Already checked that.

[tiFreak]

whoops, didn't catch that

[GreeleyGal]

Still dealing with this issue, getting really frustrated. Have more parts arriving soon. It really stinks that she looks soooo good but runs soooo bad.

[xxxJohnBoyxxx]

I bad intake gasket on cylinder #4 would definately cause your issue. Change that intake gasket and ensure you got a good seal on it and your issue should go away.

John S

[GreeleyGal]

I replaced intake gaskets when the engine was put back in but I will double check it and make sure it is seated properly. It has to be something simple/stupid that is causing the problem. I am tempted to take things back apart minus removing the cylinder head again and see if I find the problem that way and then I can visually inspect cylinder 4.

[cooljess76]

It could be a funky coil or a clogged injector as well. First thing I usually do for misfires is hose all of the boots & vacuum hoses down with brake cleaner while the engine is running to rule out any air leaks. The rubber intake boot is prone to cracking and this would give you a multiple cylinder misfire. In your case, only cyl 4??? IDK but I'd definitely still check to see if the boot is cracked. Spray brake cleaner anywhere you think air can get in after the MAF. Unmetered air will most certainly cause a misfire. Don't be shy either, soak the hell out of those hoses and boots, if you hear the idle fluctuate, you've found your leak. If that doesn't work, then you might start checking other stuff like the plug wires, coils, injectors etc. BTW, how did the plug look? Perhaps you could try swapping plugs and see if the misfire moves to a different cylinder.

[ASRACER4]

was the code 0100 0104 i had a plug wire ohm out correctly but when installed it there was a leak. if you listen carefully you can hear it snap. new wires fixed the problem.

[GreeleyGal]

Ok I will check that out. I pretty much stepped away from the car this weekend so I will see what more I can figure out this week.

[GreeleyGal]

Here is the latest, took the rocker cover off and doubled checked the gasket. It was seated perfectly fine so replaced the cover. Checked for vac leak using carburetor cleaner again and still no sign of a leak. Cleared codes restarted the car and after a few min of rough idle I have two codes, still the cylinder 4 misfire but now the code that states misfire at all cylinders. Grrrrr. I have a new cat with exhaust on its way along with the 2 Bosch O2 sensors. I also ordered an injector rebuild kit, new coil, NGK spark plugs (was using autolite), cam position sensor, and some hoses. This has got to fix it, I can't afford much more. What is the proper gap on the spark plug for the Ti? Should have everything by the weekend so I will keep you guys posted.

[xxxJohnBoyxxx]

CPS sensor and spark coil, plus wire replace and you have done it all. I don't know what to say but I can't halp anymore over the internet. I'm sorry you have a germlin that is not easy to find...


Have you checked compression on #4

[cooljess76]

Carbeurator cleaner is not a good thing to use to check for leaks. It is really bad for plastic and rubber. Nothing will dry out an oring or hose as fast as carbeurator cleaner does. Also I don't think it's as combustable as brake cleaner. So even if it did get sucked into a vacuum, I don't think it would make the idle fluctuate as much as brake cleaner would.