I have a 1998 F-150 5.4L 4x4 with 140,000 miles. I could really use some advice on what to do.

I was driving yesterday pulling a motorcycle on a trailer when my truck began to pulse and shutter slightly, and then my Check Engine light started blinking, but the blinking only lasted for about 30 seconds. The engine still stuttered, especially under load, but no CEL on. I went to Autozone to get the codes read, but it came back as PASS, no codes.

I assume that I should change the plugs and coils, but I personally have no idea how to do this. My question is what would you recommend I do? Should I take the truck to a mechanic and try to get the codes read again? Should I just get a mechanic to change the plugs and coils for me and see if that works? Would you take it to a dealer or a smaller mechanic? It puzzles me that I can't get the codes, but maybe Autozone can't read certain codes. But I would think it would read a misfure.

I went out and tried to get the light to come on again, and it still shutters when I try to accelarate, especially when I am in overdrive, and it will hardly accelerate from there.

Any help would be greatly appreciated.

 

By your description, it was a misfire. The idiot at AutoZone probably reset your PCM before trying to read the fault codes.

You can do it one of several ways:

1) Load up the shotgun and replace all the COPS and the spark plugs at once. Of course, you'll never know which of the seven COPS are still good....

2) Get it to throw a CEL again, then get the fault codes pulled by someone who knows what they're doing. Hammer on the particular driving condition that causes the misfire until you get a CEL.

3) Take it to a mechanic who has a Snap-On of equal scan tool. Scanners that can read Mode 6 data can pull the per-cylinder misfire counts and the problem cylinder easily identifed. Then, replace only that cylinder's plug and COP to repair.

Several of the COPS are very easy to replace, several are a real PITA to do.

Steve

 

I went and bought a code reader and I was able to get this code - P0304 - Cyl 4 misfire.

Do you have any suggestions for someone that doesn't know what they are doing? Should I take it in to a mechanic and get the coil and plug replaced just at cylinder 4? Or should I just try to replace the coil only and not the plug? And is this something I should attempt myself, and if so, where can I get some info on how to do it? Thx again for your help.

 

If that's 140k on the original plugs, I'd change them all.

What you can do to test the coil is swap the #4 with one of the others and see if the miss follows cylinders. If you need a coil, I'd buy a whole set from Global on Ebay, they are under $100, and single coils in parts stores are around 50 bucks each.

Do you have any friends that are experienced mechanics? Changing the plugs isn't that difficult but not something I'd do on one of these engines if I had no experience, there's some stuff that does need to be moved out of the way.

 

Unfortunately, I don't even know where the coils are to try and switch them.

I have had all of the plugs changed before, probably around 100,000 miles.

In that case do you think it would be safe to just do the coil and plug that had the misfire?

I spoke to a mechanic and they said they would charge $1100 to change all 8plugs and coils.

Can I buy stuff for cheap and make the mechanic use the parts so I won't get over-charged for that?

Then they would just charge me for labor?

 

Your mechanic is probably charging you $90 EACH for the coils - which is retail list price for OEM Motorcrafts. Any shop that does that will probably show you the door if you bring your own parts.

At full list price for OEM coils and plugs, and full book labor where labor is close to 100 bucks an hour, $1100 sounds about right. If you must have a shop do this, get them to change ONLY #4 coil. That should be less than $200.

The coils sit on top of the spark plugs. Does that help?

 

Ok, that helps, but I just want to make sure that I tell the mechanic to only change the #4 coil, but not the plug. Is this correct?

 

Well, you probably need to discuss this issue with the mechanic before you have him do the work. Let him tell YOU what he recommends and go from there.

 

Yea , have them replace #4 coil. That most likely is the problem, you can prolly stretch those plugs another 20,000 at least, if there Motorcraft.

When you take it in , have them check the heater core lines. #1 cause for #4 to fail pre-maturely in that model. They tend to leak on top #4 coil.

If they need replacing - make sure you get the Ford hoses. Ford hoses will last the lifetime of these models, but the connections don't always.- They have a brass reducer inside the return line that protects the core from pressure burst trauma. After market lines don't include that feature.

 

I had the coil and plug replaced on the number 4 cylinder and she is back up and purring like a kitten. I hope it lasts.

Thanks for the help guys.

 

It won't if one of those HC lines are leaking under pressure which is usually why #4 fails. Well, if it happens again, you'll know why anyway

Good Luck with it - hope it lasts

 

Ok, I am back with another misfire. This time it is on cylinder 2. When my cylinder 4 misfired a few weeks ago I had all of the plugs changed, and a new coil added to number 4 only. That solved the problem until today.

I am not looking to change all of the coils, mostly because I don't know how to do it or have the time. But I have no problem getting 1 coil changed by my mechanic.

So what do I need to do now? Should I change the coil on number 2? Can I get away with just changing that one coil? Am I risking another coil going out in a few weeks, and so on? What would you recommend now? Thanks.

 

You know, I think I would like to try to change the #2 coil myself, if that is all that needs to be done. Is that a difficult one to do on a 1998 5.4 4x4? Any suggestions will help. Thanks.

 

it is very easy to do. i can not recall which cylinder is #2 but all you have to do once you locate it is unplug the electrical connector, take out the 1 screw that is holding the coil in, pull it out. put your new one in and make sure its sitting snuggly on the spark plug in there and bolt it back on and plug the connector back and your all set.

 

Squirt a very large gob of dielectric grease into the boot of the COP before installing it.

#2 is second from the front on the passenger side. It's a ten minute job, easy to get to.

Steve