Little about the truck is a 2004 Fx4 with 5.4L 3v 87,000mi. Last week the check engine light came on, it was a misfire on cyl 6. Decided that it could use the spark plug change, since it was idling rough and the light was on. So this weeknd tackled the dreaded spark plug change all went fine 5 of them broke. 4 hours later finished the plugs, started her up and it was idling rough went for a test ride and the truck had no power and died twice. Check engine light came back on it was P0171 & P0174.

I researched the codes and what to look for, but Im being unsucefull finding the problem. Sprayed brake cleaner eveywhere no change, also cheked all vaccm lines and nothing. Cleaned MAF also checked FP/PCV no leaks and everything seems fine. Any idea what Im overlooking? Any help would be appreciated, Im in MD and need to drive back home to VA tom

 

Did any pieces get down into the cylinders when you were extracting the broken plugs? Did you use dielectric grease in the cop boots?

I'd pull the plugs back out and look at them.

 

Some small pieces did fall but I vaccum and crank the engine over. I did not put any grease on the boots. I pulled all the plugs and they look fine, notice that they were bone dry and didnt smell like fuel @ all

 

I had a similar misfire problem. I did the plugs, but it turned out to be a faulty fuel injector on that cylinder. A compression check showed a loss on that cylinder. They pulled the valve cover, but they eventually figured out the injector was washing the cylinder walls with enough fuel to let the rings leak.

 

Thanks! I'm showing lean bank 1 & 2, so I doubt all my injectors just went bad.

 

have the cats checked just went throught this myself I ended up removing the cats all together put a pipe in their place with extended nipples to reinstall o2 sensors .

Runs better than new now

 

Pull them and do it. This is required, not optional.

 

Those codes are lean, check everything you took off when you did the plug change. They can be caused by an air leak after the MAF. Could be something simple like not tightening the air tube from the filter to the T/B ot the small pipe from the driver side valve cover to the intake tube. Just re-double check every thing.

Also go over the PCV system/connections. If you didn't have those codes before you did the plugs then my bet is you left something un-done.

 

Thanks!I checked everything 10 times over, cant find nothing. Checked all connections, all vaccum lines including connection behind the IM. Swapped MAF and VMV with my dads truck and same problem. Im all out ideas. I figure it was something I did, but cant find anything checked all COPs connections and also injectors and nothing.

 

Did you pull the cops and grease the boots?

 

No, I haven't I will... u think it might cause that problem?

 

Please keep the ideas coming, I will keep testing and verifying everything.

 

I recommend listening to glc.

 

I will just forgot to do it, but as far as my problem I dont think that will make a difference.

 

I think it might.