Hi All,
I have a '98 Expedition, 5.4L, first owner. (44,000 miles) About a month back I started getting this staggering/hesitation/lack of power only when accelerating quickly. If I had a very light foot I'd probably not even realize it. The engine idles beautifully and always has. It's only when I demand power that I get this problem - and it's extremely annoying when I want to pass someone and the engine "misfires", or hesitates. The check engine light came on and blinked for a few minutes then shut off. This problem is also intermittent and I can't correlate any weather/temperature with when the problem occurs. In the last month, the check engine light came on only twice although the staggering has happened much more often - so the light doesn't always come on.

After reading some posts here I checked the MAF sensor and it's as clean as brand new so I wouldn't think it was that. The only other thing I can see is the 'ol #4 coil problem but I wanted to ask and see if these symptoms match first. (I understand it's a PITA to get to, ugh)

Also, since day one the engine pings - especially when the a/c is on. Ford has looked at it about 3 times and couldn't fix it. They replaced some O2 sensors and stuff like that but it still pings. The only thing that helps is if I use high octane gas. Is this normal? After reading these posts I wanted to start some mods but I read the Superchip kinda forces you into using high octane. Is the benefit worth it?

Thanks all!

 

Fuel filter, and clean the injectors with a professional "on rail" type of solvent system.

 

Ok,
Took the truck in because my front axle had a small leak. While it was in I mentioned the hesitation and the check engine light. They read the code which came up to be a "ramdom misfire" not associated with a specific cylinder. The mechanic took it on a test drive and (of course) couldn't duplicate the problem.

I also had them change the fuel-filter which upon inspection they definitely changed.

When I got it back it was hesitating. I bought some Techron fuel-injector cleaner (again) and put in a bottle - was still happening but not as bad. About 1/4 tank left I filled up with 92/93 octane and now it hasn't happened since the fill-up. Over the last 2 months or so this is the 4th bottle of Techron I've used.

Again, if I accelerate "normally" I don't even notice. It's only when I open it up (WOT) that I get the hesitating and check engine light. (I assume the problem will come back if I go back to 87 octane, since it had previously).

Question: Could it be the #4 coil problem? Ive recently read that unless the coil is failing for 2 mins. or more the computer won't register THAT particular cylinder. Since it only happens on WOT I can't really keep it going for 2 mins.

What else should I check? O2 sensors? I've also heard of the temperature sensor causing the same symptoms - ???

Thanks all!

 

I had a 97 F150 with the 4.6, It also demonstrated the same problems. The engine light came on and blinked then it went out. I brought it ot Ford and they could not fix it, I actually ended up going to a Dodge dealership to get it fixed. I had a clogged fuel injector on cylinder #6. They took all the injectors out and hand cleaned them. This is what I believe you need to do to fix your problem- and the ping to boot! Hope this helps.

T

 

Would the "on-rail" fuel injector cleaner jstang menioned work the same? (I didn't know what he was talking about until I searched around a bit). Wondering if it's better to get it done by Ford but the parts guy told me they use the same kinda kit w/ the regular cleaner - sounds the same to me. The kits are fairly cheap compared to having it done by the shop. (That is, if I'd ever have to do this again )

 

I got my kit from Mustangs unlimited, the solvent can be had at most parts stores for $9.00 ea, the kit( $50.00 ??) came with 2 cans. If you have a hard time finding a kit let me know, I'll see if I can track one down for you. tffperformance@snet.net

 

Just a thought, about your check engine light, if the computer detects problem it turn light on if part immediately returns normal status to PCM it will self clear. I would also suggest maybe taking a look at your plugs and make sure there are all firing similar, or you could have a cracked or broken plug wire. Plug wires can sometimes work great if engine is not stressed, but under WOT the computer advances the spark/ignition timing and could cause voltage drop across bad or broken plug wire.

 

I too had the same problem after installing a Jacobs ignition. Pull the plug wires off (on the 5.4 you probably have to pull the coils). Inspect the plug boots for evidence of miss-firing to the block. You will see a chalk like powder in them. Replace the wires after coating the inside with non-conducting (spark plug) greese. This should solve the problem and it is a cheap fix. Cost very little to try and I bet that is the problem.

 

Well, ok... I was hoping I could get away from messing w/ the coils, etc. because of what I've been reading about the 5.4. I took a look last night and aside from the #4 under the dash the rest don't seem too bad. (1. Open mouth; 2. Insert foot)

Thanks for the help guys.

 

Ok - checked the #4 coil and... add another to the statistic. The underside of the heater hose above the coil was caked with an anti-freeze+dust mixture. The coil, of course, was also covered. I removed the coil but didn't see ANY cracks on it. (???) The plastic on the top of the coil was a little deformed, though. Comparing it to the others I could see some damage but only on the top.

Anyways, sent the wife to get a new coil... $97!!! Ugh!

Been a week now and it's been running great. Thanks for the help, guys.

BTW, I couldn't get to the screw on the clamp since it was facing the other direction so I ended up adding another clamp in front of the existing one (closest to the firewall).

 

It looks like you may have gotten her taken care of, finally. If the problem comes back, and I'll keep my fingers crossed, about not Jinxing the whole thing...

I had a plug insulator that had a fine, hairline crack in it. The only time she acted up, was after the engine had been running for awhile, 30 minutes or more. It would miss, spit, sputter a lil', when I had to accelerate at half throttle or better.

If you haven't changed your 100k plugs (YEAH RIGHT, sure they are...), you may have them changed/checked. This problem drove me nuts for months, before I just decided to change the plugs on a whim.

R1968