Hey guys! Not too long ago I had a problem changing my plugs but managed to get through it. Originally I set a few soft codes for engine misfire and had some perfomance issues that have been resolved with changing the plugs. And all seemed good immediately after changing them.

However now I seem to have an issue where the idle drops pretty low and sometimes seems as though its too low and may stall but is smooth nonetheless. Also since changing my plugs my fuel mileage went up (had atleast one misfiring plug) immediately and now is back down to roughly where is was before plug change. Also I suspect a mis as I hear the skip at idle that I heard before plug change.

Also even before I changed the plugs I noticed a faint sound from up front that kinda sounded like a wheel bearing. However it is directly related to throttle position in that I hear it under light throttle but if I back off it goes away so I know its not a bearing and believe it to be fuel system related.

So here is my question. Since I didnt replace the Coil Packs when changing the plugs I believe they may be a/the problem however since I hear a noise that appears to be related to engine demand is this an injector problem? So before I mindlessly go ahead and assume its the COP's or Injectors what do you guys think it is?

Thanks as always.
-Shifty

 

For anyone to help, they will need to know the year and which engine.

 

Probably should clean the throttle body IAC and MAf.

 

Oops....

Sorry its an '04 new body style with a 5.4 3Valve

Have Champion plugs now. Running and Edge Evolution and can monitor many values. Noticed drop in fuel mileage and RPMs drop pretty low when coming off throttle to hi 300's sometimes

 

Its been reported by some members the champion plugs are failing prematurely.. I would only use Motorcraft or perhaps Denso or NGK..

 

Yes, I hated to say it, but some have had a problem with the Champions, and that will be the first suggestion. Pull them and replace with Motorcraft(after applying nickel anti-seize on the shanks). You may want to eliminate some other possibilities first.

 

Wow....theres a job I was hoping to avoid doing again. They should come out fairly easy seeing as how I put anti sieze on them a month ago. This still doesnt account for the faint whurring sound though as it was prior to and post changing plugs.

What could I expect from a failing COP or Injector?

Is there an updated ford plug or do we have to put the same pieces of crap back in? Part no.?

 

Normally, when an injector fails, it stays open and leaks fuel into a cylinder. It would be running rich. You can test them by removing the injectors and visually checking to see if it leaks.

 

3v cops are avalible on e-bay search DG511. Not sure how much they are but the 2v's are only $80 a set. I would try cleaning the throttle body (be extremly careful because its electronic clean the electronic parts with electrical parts cleaner only) clean the MAF. There is no IAC on that engine. If your missing you should have a CEL if you do have a CEL and its a missfire code jettison the Champions and get Motorcraft,Denso or NGK while your at it get the e-bay coils and replace them.

 

Throwing no codes and really have no perfomance problems to speak of as I have lots of power. When I was running the factory plugs and they were acting up I only had the odd soft code show up now and again but it did fall flat on its face from a stop occasionally and had a serious misfire (without code) at freeway speeds that behaved like a shifting problem.

Im pretty pissed that it may be the plugs that I just friken put in causeing the loss in fuel mileage.

So you are saying that the faint noise Im hearing could be throttle body? If not what would a fouled throttle body cause? Poor performance? Wouldnt I notice a reduced performance across the board? So I would take off intake tube where it meets intake and that is throttle body correct. I dont want to assume anything on this engine anymore.

 

The noise could be cam phasers but that usually described as a knocking sound. The throttle body controls the idle and the MAF influences it to thats where I'd start. Cleaning the throttle body and MAF really costs nothing except some solvents like deep creep and CRC electrical parts cleaner(you need a 20 torx safety bit to disassemble the MAF) and doing it is a maintenace deal your truck WILL run better after. It may cure the idle problem as well. Where dose the noise come from? its unlikely fuel system. might be your belts shot.