truck has been running great until i hit 100k ..it started to run rough so i did a tune up ...new plugs, wires, air filter, fuel filter, injectors cleaned and new o2 sensor since the check engine light was on...that took care of everything except i keep buring up a plug in cylinder number 3...once a month is starts to run rought again i pull that plug out and the enitre center of the plug is gone(burnt up)

not sure what else to do or what would cause this?

AG

 

Its running lean on that cylinder.

Probely a Partially clogged Fuel Injector, assuming its EFI.

later,
Dustin

 

it is EFI....i just had the injectors cleaned 3 days ago and replaced the spark plug again 2 days ago.....so maybe that will fix the problem(i hope)

 

Did you replace all 3 O2 sensors?

 

no i only replaced the upper o2 sensor on the bank for cylinder 1,2, and 3...should i replace the other side and back one too?? i dont want to waste money on them if thats not the problem

thanks

 

I recently had the same problem and I had to replace all three change all the plugs and I also replaced the EGR valve and EGR tube to get everything operational again. I used a code reader and it gave me a total of 15 codes I had to deal with. I would wait and see if it continues and if so I would replace the rest of them.

 

if i replaced the 1st one but not the other 2 would it make the 1st one go bad?...i just bought the other 2 so i am going to put them in now...i dont know where the egr valve is?

 

If your check engine isnt on then its not a 02 sensor.

Besides, 90% of the time a O2 sensor is bad it runs rich, and rich will foul plugs, not burn them up. Your getting to much air into that cylinder, thats why im thinking your having a clogged injector, or a blown head gasket allowing it to suck air in from other places.

later,
Dustin

 

the head gasket was replaced by ford about 4 months ago....but i guess it could go bad again

 

Listen it is not your head gasket it could be your O2 sensors but if your check engine light has not come back on don't bother replacing them just yet. As far as your engine running rich if your O2 sensor goes bad is not true at all it can go either way I had 1 plug that was getting fouled and the other 5 were getting burnt. the O2 sensors control the air-fuel mixture. If they go bad they can call for more air or more fuel it all depends. Like I said before The local dealership told me I had a blown head gasket and they could not be further from the truth. I have also been told by plenty of mechanics that if it is a blown head gasket to just replace the motor because it could end up costing more than its worth to do a head gasket job.