Hey all,

Been lurking for a bit.

Just purchased a 2005 FX4 Screw with 39K on the odometer a few weeks ago. Obviously it was barely driven, but the previous owner did feel the need to have it lowered. Luckily he kept all the original parts, and I had it returned to stock +plus some Monroe coil overs on the rear to help with handling my 24' travel trailer.

Since they did the work I have noticed that at freeway speeds it will sometimes shudder and have what feels like a misfire. I plan on bringing it back into the shop, but I am preparing to figure out what it is suspecting that they will not accept that they did anything.

While it could be a million things, a dying fuel pump perfectly describes the issue that I am having since it's pretty much existent only @ freeway speeds.

I have a USB ODBII reader and Scanmaster-ELM and am not able to detect any misfire's or codes, even while it's happening and the laptop is hooked up. I am not very good with the program though.

Can anyone offer any suggestions on what it might be? Is it possible that during the conversion back to stock a fuel line or wiring was affected that would only cause the problem to happen at freeway speeds?

Could the pump really be going out with so few miles on it?

The plugs have never been changed, I confirmed with person I bought it from and he was the original owner. He had also never washed the engine or anything.

 

I suppose it's possible you have some fouled plugs with only 39k on it.

Before suspecting the fuel pump, I'd suspect the FPDM. Cheaper and a lot easier to change. I'd also change the fuel filter on general principle.

 

I dont mind changing the plugs although I hate to just throw money at it, especially when it's not throwing any codes. I will need to invest in the Lisle tool first.

I will inspect the FPDM, been reading about that as well. I think my location would make mine less likely to be damaged, except by electrolosis, but would this be something that would be intermittent? My reading suggests thats its more of a total failure than an intermittent problem happening only at highway speeds, but I maybe I didnt read the right threads.

Fuel filter is getting changed this weekend, thanks for the suggestion. The price and ease of replacement is an obvious place to start.

Still it's odd that the problem started only after having the suspension worked on.

 

Also, the 05 5.4's had a bad batch of fuel injectors - they extended the warranty on them to 11 years/120k miles.

 

Yeah, I just learned about that tonight on this forum. But I dont think its related, everything I read describes that as very violent and something that does not just go away.

After reading more on the FPDM I think I might just throw the $60 at the part and have it replaced. Found a thread where someone was having almost identical issues. That and the filter are pretty cheap, easy, and preventive maintenance anyway. If its not either at least I have narrowed down the possibilities.

 

My 05 had a similar problem...

If it happens when it goes into overdrive its most likely a misfire...and you have to get it to misfire pretty bad for it to give a code...

I did have an injector go bad, and it fried the head and cat on the passenger side...when that was happening, it would act like it was flooding, but at freeway speeds... so check the injectors...

Hopefully its not a bad cat cuz you are gonna be in for a big surprise at the cost of replacement ($2400 just for each cat) as no aftermarket are available here in CA!

Regards!

 

being that it only happens on the freeway i would guess its plugs. does it happen on level or a slight incline when you barely put your foot into it (not enough for it to down shift though)? that sounds like plugs to me. and you are aware of the plug issue correct?

 

*IF* a faulty injector cooks the cat, that's covered too. Collateral damage is covered.

 

Wouldnt that be covered under the extended warranty if the injectors caused the problem?

I do not believe that is the case, both cats are reading the same temps per the ODBII readings when I was driving on the freeway.

Seems like an easy enough test though with a multimeter.

 

Exactly this ^^^^

So you sound like your pretty sure that it's plugs if that is whats happening, and the answer is yes. I took a drive on Sunday going slightly uphill and it was as bad as its ever been until the incline got steeper and it went away. This was all on cruise control BTW. On the way back down the hill it did nothing at all. If by plug issue you mean that they do not like being extracted from the engine, then yes. I ordered the Lisle tool yesterday from Amazon, should be here this week. I plan on trying the impact wrench method, since there seems to be a lot of great feedback on that from people who have done both ways.

 

ya, totally sounds like plugs in my opinion, and from all the other threads on here with people having misfires, doing plugs, and solving the problem. and yep that is the spark plug issue, and it sounds like you know what youre getting in to if youve bought the tool and are using the impact method. guys like to run something through the gas tank such as techron to help remove the carbon. my dealer had a fancy name for it, but same idea. i went with the dealer method just because it was 325 for parts and labor no matter how many broke

 

I guess I will have to figure out the total cost and see if its worth it to do it myself. Initial cost is obviously higher.

Can anyone tell me, with the impact method, should I be using an normal spark plug socket on the impact wrench or an actual impact socket?

 

I don't think you can fit an impact socket down the hole. Use a 6 point Ford 3V plug socket. You don't want to use a big 1/2 drive air impact, use a small electric one.

 

So I replaced the FPDM and fuel filter this weekend. Visually nothing wrong with either, but for $60 I figured it was preventive maintenance.

Took it out to lunch just now and no problems at all. It is a bit warmer than it has been at this time of day. Is it possible that alone was enough to keep the problem from happening?

I plan on pulling my trailer on memorial day and wondering if I should move forward with the plug change. I am not against doing it, but I have a lot going on right now so if I could wait that would be awesome. Last think I want to do is get on the road to find out my truck is having a hard time with the trailer.

 

I'd hook up the trailer and do a dry run.