Help with codes and engine missing in a 96 Town Car

[Blown&Injected]

Got some great help for my Explorer a while back, anybody know what to do with this condition?

1996 Town Car has a slight miss. Took it to Auto Zone, they pulled the codes:
P0303 cylinder 3 not firing.

Replaced the plug and wire for number 3 = same problem, even replaced the plug and wire for the cylinder that shares the coil with number 3.

Disconnected the battery, drove a short while and the light comes on. Go back to Auto Zone and now the computer says:
P0304 cylinder 4 not firing.

Did the same thing to the other coil pack for number 4 and shared cylinder as I did for number 3 when the computer said it was 3 that was not firing.

Actually I said "I", it really is my father that was fooling around with his car and I am just trying to relay what he told me.

We thank you for the help.

 

[xlr8ngn]

First make sure you are getting spark at the specified plugs. A misfire can also be fuel related. Check the fuel pressure, injector drive signal, and all the vacuum hoses. Could be a bad injector. The misfire monitor can also be affected by the evaporative emission system. Check the carbon canister, purge solenoid, all lines. If there is raw fuel in the canister replace the canister. If everything is still ok, may want to do a compression test.

 

[xlr8ngn]

BTW is this continuous or intermittent?

 

[Blown&Injected]

Thanks for the help.

It is a continuos problem that is most pronounced under a slight continuos load.

It is interesting that you mentioned fuel/injector issues. My father told me this happened just after taking the car in for routine service that included a new fuel filter.

 

[wlaukaitis]

Well
I had a P0303 which is a generic code (not manufacturer specfic) on my 99 Maxima. I cleared it a few times, sometimes I got a P1320 which is manu specific ( a P0*** is OBDII generic and a P1*** is specific) a "Random cylider misfire) but P0303 came up the most.

So I swapped the #3 and #4 coil and kept gettting a P0304 for cylinder 4. So I knew that coil was bad (originally #3 coil)

This happened 2x, 2 different coils.

So if you can, swap the coils even if it fires 2 cyliders like our beloved Buicks

 

[Blown&Injected]

Still looking

 

[87gninpa]

try module and coilpack? thats what caused the cylinders on my GN to misfire without rhyme or reason....

 

[TurboJim]

Originally posted by wlaukaitis
Well
I had a P0303 which is a generic code (not manufacturer specfic) on my 99 Maxima. I cleared it a few times, sometimes I got a P1320 which is manu specific ( a P0*** is OBDII generic and a P1*** is specific) a "Random cylider misfire) but P0303 came up the most.

So I swapped the #3 and #4 coil and kept gettting a P0304 for cylinder 4. So I knew that coil was bad (originally #3 coil)

This happened 2x, 2 different coils.

So if you can, swap the coils even if it fires 2 cyliders like our beloved Buicks

Actually P0300 is random misfire.

I'd throw plugs and wires at it. Asuming their original or very old. The plug extensions are common to leak voltage and arc to the cyl head. This is assuming its not direct soark. I forget when they switched to that, like the 5.4's. Also, make sure he's not using Bosch Platinum plugs, use the motorcrapt specific plugs for the car.

Hmm, 96, I cant remember if this is the year with the plastic upper intake. If it is, the seal to the lower intake is common to leak. This causes a vacuum leak at speccific cyls, but you usually will have a system lean, or adaptive trim at max (forget the numbers offhand) codes stored as well

As was mentioned up above, could also be an injector, but I think you said the miss occurs under high load? Thats typically secondary ignition. Again, TYPICALLY.

 

[Blown&Injected]

WOW thanks for all the ideas guys.

One of the Mods here is works for Ford Service but probably will not help - I was counting on his strong Christian conviction since I had to call him on a lie, but I guess his conviction is just talk - not action