THE-HOWARD

iTrader: (1)

Hey guys so for some odd reason my 2000 ws6 has a random misfire on cylinder number 6. The problem is that I can not figure out why and its pretty bad to the point I can not drive the car. The good news is that I know its not a bad coil because I switched the cylinder six coil with cylinder number one and it was doing the same thing. The car has brand new plugs and wires. So now I narrowed it down to its either o2 sensors or a bad computer but here's the problem how can I test the computer on my car to see If its bad.

THE-HOWARD

iTrader: (1)

Hey guys so for some odd reason my 2000 ws6 has a random misfire on cylinder number 6. The problem is that I can not figure out why and its pretty bad to the point I can not drive the car. The good news is that I know its not a bad coil because I switched the cylinder six coil with cylinder number one and it was doing the same thing. The car has brand new plugs and wires. So now I narrowed it down to its either o2 sensors or a bad computer but here's the problem how can I test the computer on my car to see If its bad.

the car has long tubes ory and a lid. any info would be appericated

Titanws6

iTrader: (35)

I'm gonna shoot for plug wire, try swapping that and see. Even if it is new, it still could be defective.

THE-HOWARD

iTrader: (1)

I forgot to add I did that too and its still the same thing

RPM WS6

iTrader: (3)

How did you determine that? Do you have reason to believe that the PCM is not sending the proper signal to fire the #6 coil?

Are you sure that the #6 fuel injector is operating properly?

Have you also considered the possibility of a valvetrain component being at fault (broken valve spring, bent push rod, bent valve)?

THE-HOWARD

iTrader: (1)

Ttt...

Dskeet6

iTrader: (20)

make sure the terminal to the coil packs on that bank is clean just trace wires to plug and see if you find anything... I would recommend turning the motor over with the plug out and grounded to see if it is ignition.... if not its mechanical

THE-HOWARD

iTrader: (1)

The push rods are brand new and when I did that the valves looked fine

jimmyblue

iTrader: (11)

Swap injector #6 with some other and see what that
does.

I've heard that sometimes the indicated cylinder is not
the real one. But in my experience with a bad plug wire,
it was right.

.cammedZ

iTrader: (4)

I would try swapping the injector. You can use a noid light to see if the PCM is firing the injector. Did you verify the coil is actually firing? If there is a problem in the circuit swapping the coil will not effect anything. Also If you rule out fuel and spark you will need to do a compression and/or leakdown test on that cylinder. You should verify you have no intake leaks. Start with the simple and obvious. A bad O2 sensor will set a code 99% of the time and if it doesn't it will typically give you random multiple misfires on that particular bank of cylinders not just one. A Bad PCM is possible if a driver is burned out, but improbable and least likely to be the issue.


Jimmyblue- You are correct, sometimes the cylinder that shows the misfire is not the one that is actually misfiring. These are sometimes hard to diagnose. It happens because of how the PCM sees the misfires through the crank signal. In my experience when this is the case it is usually the companion cylinder that has the issue. However we have no reason to think this is the case here.

PNYDRPR

I had the same problem but it was my # 8 and it was dirty injector so def try cleaning it

71novaguy

iTrader: (2)

I'd still check the spark plug. I had some new bosch platinums in my other car, had less than 10k miles on them when I developed a miss. I checked everything else but that for weeks. then one day a friend of mine said "plugs are cheap". so i replaced the plugs and the issue went away.

THE-HOWARD

iTrader: (1)

Thanks for all the info guys really appericate it but it turned out to be bad gas that I got from a marathon station the other day. I pretty much drained all the gas in the car and filled it up with bp gas and after some driving the car came back to normal

71novaguy

iTrader: (2)

how did bad gas make it misfire on only 1 cylinder

The Mighty Texan

iTrader: (4)

^This. I'm expecting this thread to continue on here shortly. Bad gas would only cause that if one injector was plugged up and not letting it flow through or something like that, in which case, the underlining fault is not the gas (entirely at least).