Misfiring

[joey b]

My car seems to be misfiring. I have a new ICM and it seems to be only the #6 cylinder. I changed the plugs last week and the 6 plug was rather black. I tested the resistance on all of the wires and they all check out great.

 

I put 2 bottles of fuel system cleaner in the tank (one lucas, the other valvoline full fuel system treatment). The first seemed to help a bit, but now it hasn't gotten any better.

 

The car misfires sporadically. At idle, at cruise speed, and at WOT. It misses more at highway cruise speeds.

 

Is there any way to test individual injectors? Would an injector fire intermittently good to bad at any random time? Is there any way to test the ignition coils?

[slick]

For injectors, you can ohm them out to see where they are sitting at. There is really no good way of testing coils.

 

Does this miss really affect the driveability, or does it make the idle just a little rough? I'm just trying to see how big of a miss it is(like it's only running on 5 cylinders, or if its a minor miss).

[Robby1870]

injectors should be around 12 ohms

[joey b]

It misses BAD, when it does. Lightly pressing the gas will cause the torque converter to lock/unlock causing the car to buck very badly. If you hold it and run to 5K it shifts very hard. Slow as piss as well. From looking at the plugs, only the 6 cylinder had the black plug. The gap was unchanged.

[joey b]

I am still having problems with it. Misfires, smell of gas.

 

New O2 sensor, plugs, ICM

Coils test good, wires have low resistance

Crank sensor has read at ICM MAP sensor gives accurate reading

New Fuel Filter and about 6 bottles of injector cleaner

All injectors test between 12 and 14 ohms

 

What about that purge canister, runs back to the gas tank, does that affect anything?

[slick]

Odd.... If I were you, I'd take it somewhere and have the codes pulled. Even though it may not be throwing an SES light, there still may be a code or two.

[joey b]

but I don't have a cat or EGR, are they gonna give me shit (BTW, I'm not going to a stealership)

[slick]

I'd just go to like autozone or something like that. They will usually read your codes for free, assuming they have the correct cable.

[Spoon]

Have you checked compression on that cylinder? low compression will cause excessive fuel on the plug.

[joey b]

Pulled all plugs, cleaned (they are only 1K old) and cleaned connectors at both ends of wires. Checked wire resistance. Ran great for about a week. Started acting up again. Pulled all plugs, cylinder 3 had a fuel drenched plug. Moved plug to #2 cylinder and cleaned it up (maybe plug is bad). Put new wire to #3 cylinder. Runs fine now.

 

I am worried that the #3 cylinder may not be compressing as it should. We'll see.

[slick]

Ouch, that might suck. BTW, are you low on oil come time for oil change?

[SleeperRed90TGp]

I am still having problems with it. Misfires, smell of gas.

 

New O2 sensor, plugs, ICM

Coils test good, wires have low resistance

Crank sensor has read at ICM MAP sensor gives accurate reading

New Fuel Filter and about 6 bottles of injector cleaner

All injectors test between 12 and 14 ohms

 

What about that purge canister, runs back to the gas tank, does that affect anything?

 

As slick94prix said and I have said many times. YOU CAN"T TEST THE COILS TO SEE IF THERE GOOD.

 

Read.

http://www.w-body.com/forum/viewtopic.php?p=271413&highlight=coil#271413

 

Jud