MISFIRE in Cylinder 6
 

Check engine light is on. Code reads misfire in cylinder 6. Put new plugs and wires in, no improvement. Swapped out ignition coil, no improvement. Power seems to max out around 3500-4000 rpm. Whats next? Is it bad to continue driving it with a misfire???
Please Help...
2000 Ext. Cab 3.0 Litre 5spd 2WD 81000miles

not sure if its bad to keep driving it with a miss but it cant help anything. when you took out the plug on cyl6 what did it look like did it have any flim on it,did it smell like gas,did it look like coolant had gotten on it? next i would be doing a compression check on the cyl and a coolant system pressure check to make sure you dont have a blow head gasket

I think I have the same exact problem, and I believe it's head gasket or cracked head...Started mis-firing really bad. ODB gave a code of 0306 = #6 misfire. Removed plug...it was clean and dry and no smell of anything on it. Replaced coil ($120 !)and still no improvement.

Further clues leading to head gasket/head: smell of antifreeze after it's been running. Occasionally the overflow tank will bubble after it is shut off (but never seems to use or give antifreeze). Pressure check of radiator/cooling system showed the pressure while engine was on, as 16psi and climbing. Since it's a 15 or 16 lb radiator cap, that would indicate to me, that something other than heat, is pushing the coolant out towards the cap.

So, 1) how much of a pita is changing the head gasket out? (I'm a chevy guy) and 2) what are the odds it's more than just the gasket - ie crack in head or worse, crack in block or distortion in block? I really don't want to pull the whole motor out, as it's February here in Virginia and dreadfully cold and I don't have heat in my garage

I guess I will pull both heads, and have a machine shop go over them for cracks and warpage and if they check out, put them back on. Ugh...

Yep, mine's the #6 cylinder - the head gasket was blown and there's a water jacket right next to the tear. Case closed.

that could be.. mine read cylinder 6 misfire and it ended upo being the injector fucking up.. bought a new injector and it runs perfect..outside of my new fuel pproblem.

How did you know it was your injector? I'm wondering if I should replace all of mine, since it's all torn apart now. They're not cheap, though. Thanks

Newbee to the site
 

I appreciate the welcome...I have a 2000 Rannger 4x4 Super Cab. Posi trac from the factory. I had an old (1986) Ranger 4x4 Extended Cab that I had rebuilt, and eventually sold. Always had wanted another one, so I purchased this one in Nov. Just finished up the tie rod ends, and ball joints and upper control arms. It had large tires on it when I bought it in San Antonio, and when I got back to Missouri changed to the correct size. If nothing else, it is alot quieter. Doesn't look as good, but performs as well. Randy:)

Had the same problem on my daughter's 99 cougar V6 2.5. I ran the codes, changed the IAC (idle air control) valve which did not help, then the coil pack, didn't get rid of the misfire codes. Took it to the local shop, and they changed the intake gaskets....that solved the problem. Randy

I changed out everything ignition related on mine and rearranged my injectors,no improvement ,,turned out being a burnt valve,,2004 3.0 with 60k on it,,,,jim

Did you repair the valve yourself?

Burnt Valve?
 

I noticed a clicking/tapping noise from the bottom of the motor, could this be a burnt valve?

hey Steve ,,,I coundnt have the truck down so I bought a new head from Ford and did it on a Saturday. Worst thing about it now about 6 month's later it got rough again and threw a code I have a miss fire on the other side!....I should have done both heads when i had it apart. At the time I just figured it was just a defective head,,didnt realize it was a common problem with these..
Im not a pro engine builder but my guess is the springs they put on these are so light weight that I could almost undo them with my fingers,Ive heard they do this for efficiency but I suspected valve float and the EX valve not always seating at high rpms, Remember the only time an exhaust valve cools is when it hits the seat..
but im hearing rumor out here that it may be a lean tune in the computer so who knows for sure...jim

yeah it's definitely a lean tune in the computer maybe.

Definitely maybe?

the same exact thing happened to mine i think.