cylinders 5 and 6 misfiring?
 

i just bought a 97' cobra this week and when i got home from the hour drive the car was idling a little rough. i took it 2 auto zone to have it hooked up 2 a scanner. they said cylinder 5 and 6 were misfiring. is it the injector, spark plug, wire, or what could it be? i than noticed my driver side first cat was glowing red, is it clogged or could it be from the cylinders misfiring?

Since you bought the car used, my frist step would be to change the plugs.

If that doesnt work, then the next step is to switch around 5 and 6 boots to a different location and see if the code changes.

well with the cat glowing red you could upgrade your exhaust now... But I would ohm out the injectors, check/replace plugs and wires if it has been awhile...

how do i find out which cylinders are 5 and 6?

If you have a Hanes manual itll say in there. For the 2v's #1 is front pass. side, rear drivers side is #8.

Glowing cats? Ain't that from too much fuel getting to them? Would that make sense with a misfire? Not ignition, so you get straight fuel dumping to the cat and the cat burns? Seems to me that this is all electrical.

What all is done to the car? When he pulls the plugs we will see if the car has been running rich or lean.

if the cats glowing then your car isnt burning the fuel and its instead igniting in the cat which is bad. this will melt it and turn it into a big clog which will hurt power,mpg everything. You dont have a fuel problem you have a spark related problem. Could be coil packs,plugs,or wires or even possibly something else.

Start by pulling the plugs off numbers 5 & 6 and looking at them or better yet grab a pic for us to help you out more. But i can allready guess they will be death black from fuel that isnt getting burned.

the car doesnt have much done to it. its got moser 31 spline axles, 4.56 gear, k&n air intake, thats about it, nothing really mechanically. well i heard it might be the fuel injectors so i took 5 and 6 out, as well as the spark plugs...spark plugs black as hell. as for the injectors i noticed that both had small cracks on the top of them. went 2 swap for some used ones my buddy gave me and color didnt match. mine are blue and the used 1s were orange, 19 lbs i believe? tomorro im gettin the right 1s and finishin up, ill let u guys know how it goes.

yours are 24lb IIRC. I'll bet that the injectors are hashed and sticking open too long thus flooding the 5 and 6 cylinders and causing carbon buildup on your plug which makes the cylinder not fire and causes raw fuel to be ejected into your cats. Replace all the injectors, your fuel filter, and all the plugs. Also, if the cat was glowing red... it's probably toast too so replace them or cut them out and go catless till the rest of the problem is fixed.

my dumbass only thought the injectors were cracked, that was just a plastic ring that went around the top so the o ring wouldnt slide off. well injectors swapped and same cylinders still misfiring. also took off factory midpipe and put on x-pipe w/out cats. now the exhaust smells like raw fuel. i can rule out any fuel problems now right?, i mean from what im seeing the fuels getting there, just not being ignited. like i said earlier in this thread, i swapped the 2 plugs that were misfiring. if it were plugs it would be good now right? or would i have to switch all plugs 2 get those 2 to run good?

I would go with, like spike said, pretty much a brand new ignition: coil packs, plugs, wires. Replace everything instead of just 5 and 6 cylinders. If that doesnt work, i think it might be time to run through the cars electrical system and see if you can find any problems. Another option would be to call the previous owner and see if they hade any problems like this before with the car.

I had this problem, and it ended up being a very small vacuum leak due to a small tear in the part of the pcv hose that connects to the valve cover, it was causing my engine to load up with fuel, specifically cylinder 2 in my case, causing a misfire in that cylinder. I didn't realize what was causing the misfire until the tear got large enough that it made a hissing noise and caused the engine to barely run. Anyway check all of your hoses and such in case thats causing your problem.

Try to see if you are getting a spark on 5 6. Pull the plug while car is on, it should run worse if it stays the same theres your problem. You could also switch coil packs to see if problem jumps to 2 other cylinders 1-4 or if its stays on 5-6 that would mean the coil pack is bad.

I would do exactly as Venom suggests....but don't pull the plugs, just unplug the coil plug while the car is running. Swapping the COP's will help you determine it it is a COP issue. You could also borrow a COP from someone too.

Blake, 97 cobras dont have COP like your GT only two coil packs.

problem fixed...holy crap, who woulda thought that the problem was the two wires on the wrong cylinders. i wonder if switching the injectors played a role in this at all, probably not.

Good that you figured it out without wasting any more money on parts.